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1
Mahadevan, Sankar. "Developing a Vehicle Hydroplaning Simulation using Abaqus and CarSim." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/79699.
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Tires are the most influential component of the vehicle as they constitute the only contact between the vehicle and the road and have to generate and transmit forces necessary for the driver to control the vehicle. Hydroplaning is a phenomenon which occurs when a layer of water builds up between the tires of a vehicle and the road surface which leads to loss of traction that prevents the vehicle from responding to control inputs such as steering, braking or acceleration.
It has become an extremely important factor in the automotive and tire industry to study the factors affecting vehicle hydroplaning. Nearly 10-20% of road fatalities are caused by lack of traction on wet surfaces. The tire tread pattern, load, inflation pressure, slip and camber angles influence hydroplaning to a great extent. Finite Element Analysis, although computationally expensive, provides an excellent way to study such Fluid Structure Interactions (FSI) between the tire-water-road surfaces. Abaqus FSI CEL approach has been used to study tire traction with various vehicle configurations.
The tire force data obtained from the Finite Element simulations is used to develop a full vehicle hydroplaning model by integrating the relevant outputs with the commercially available vehicle dynamics simulation software, CarSim.Master of Science
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Björn, Jonathan. "Simulation of a Clinch Unit by using Cosmos and Abaqus." Thesis, Jönköping University, JTH, Mechanical Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-8134.
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The following report contains an evaluation of the use of mathematical simulation programs at the company Isaberg Rapid AB. The work includes booth FE and motion simulations where the results are compared with real life test data.
The goal of the report is to evaluate the accuracy of simulations which can be performed by engineers as a part of the design process. By using mathematical simulation tools it is possible to find a good design solution early in the development phase and thereby shorten lead time and reduce costs.
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Ogmaia, Daly, and Sebastian Elias Tasel Tasel. "Simulation of vehicle crash into bridge parapet using Abaqus/Explicit." Thesis, KTH, Bro- och stålbyggnad, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-169436.
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Safety is an important aspect when designing bridges and roads. One aspect among others to consider is the road restraint systems. The focus of this study was centered to safety barriers which are the vehicle parapets/guardrails. The parapet must meet certain requirements specified in European Standard in order to obtain a CE-marking, indicating the acceptance of use. Full-scale test must be performed for a proposed parapet to evaluate the performance. Often several full-scale tests are performed in order to achieve CE-marking, making it an expensive process. The primary objective of this master thesis was to investigate if Abaqus/Explicit could be used as the finite element software for simulation of crashes. Secondary objective was to investigate how well a performed full-scale crash could be simulated in Abaqus/Explicit. A full-scale test was conducted and the parapet installation and vehicle used was modeled. Same conditions as in the full-scale were used in the simulation. The results indicated that it is possible to simulate the full-scale crash using Abaqus/Explicit. However, the behavior of the full-scale test was not completely captured. The maximum dynamic and permanent horizontal deflection of the tabular thrie beam in the full-scale test was 582 mm and 515 mm, corresponding value from the simulation was 703 mm and 643 mm. The conclusion from the results is that Abaqus/Explicit is a suitable finite element software for simulating crashes. The differences between the full-scale test and the simulations in this master thesis were due to the simplifications and assumptions used when modeling the parapet, bridge deck and the vehicle. The overall global behavior of the full-scale test was not captured, however the simulation results were not far from the full-scale test even though rough simplifications and assumptions were used in the modeling. We believe that with more care to details in modeling, it should be possible to have better convergence between simulation and the full-scale test.
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Saha, Ujjal kumar, and Adis Avdic. "Simulating a tensile test of a carbon fiber composite test specimen in ABAQUS." Thesis, Högskolan i Skövde, Institutionen för teknik och samhälle, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-5173.
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This work aims at providing a numerical tool for the efficient design of the multidirectional carbon fiber reinforced composite material by means of finite element simulations. Abaqus/ CAE v 6.9-1 software has been used to establish a 3D model for simulation of the tensile test on the composite specimen. The aim of this analysis of multidirectional carbon fiber reinforced composite is to predict the strain and stress distribution in different plies through thickness. Tensile test experiment was carried out and the result was analyzed by ARAMIS to calculate the young’s modulus, stress, loads and strain of the composite specimen. The numerical model was compared against the result obtained from tensile test experiment to arrive at meaningful results for validation. This is done in order to understand the mechanical strength and strain at failure of the composite material. In this work three types of CFRP composite specimens are used, all have same 15 no. of ply but stacked in different orientation. It is found out that mechanical strength, failure load and strain differ slightly depending on this different ply orientation. A series of different modeling technique has also been done to verify the best modeling technique. The micromechanics of composite material is complex and the experimental predictions are time consuming and expensive. Though using FEM frequently solves the problem.
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Elofsson, Johan, and Per Martinsson. "Welding simulation with Finite Element Analysis." Thesis, University West, Department of Technology, Mathematics and Computer Science, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-827.
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Segle, Peter. "Numerical simulation of weldment creep response." Doctoral thesis, KTH, Materials Science and Engineering, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3359.
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In-service inspections of high temperature pressureequipment show that weldments are prone to creep and fatiguedamage. It is not uncommon that severely damaged weldments arefound even before the design life of the component has beenreached. In order to improve this situation action has beentaken during the last decades, both from industry, universitiesand research institutes, aiming at an enhanced understanding ofthe weldment response.
The work presented in this thesis focuses on numericalsimulation of weldment creep response. For a more profoundunderstanding of the evolution of creep damage in mismatchedlow alloy weldments, simulations are performed using thecontinuum damage mechanics, CDM, concept. Both design and lifeassessment aspects are addressed. The possibility to assessseam welded pipes using results from tests of cross-weldspecimens taken out from the seam is investigated. It is foundthat the larger the cross-weld specimen the better thecorrelation. The advantage to use the CDM concept prior to aregular creep analysis is also pointed out. In order to developthe CDM analysis, a modified Kachanov-Rabotnov constitutivemodel is implemented into ABAQUS. Using this model, a secondredistribution of stresses is revealed as the tertiary creepstage is reached in the mismatched weldment.
Creep crack growth, CCG, in cross-weld compact tension, CT,specimens is investigated numerically where a fracturemechanics concept is developed in two steps. In the first one,the C*value and an averaged constraint parameter areused for characterising the fields in the process zone, whilein the second step, the creep deformation rate perpendicular tothe crack plane and a constraint parameter ahead of the cracktip, are used as characterising parameters. The influence oftype and degree of mismatch, location of starter notch as wellas size of CT specimen, is investigated. Results show that notonly the material properties of the weldment constituentcontaining the crack, but also the deformation properties ofthe adjacent constituents, influence the CCG behaviour.Furthermore, the effect of size is influenced by the mismatchof the weldment constituents.
A circumferentially cracked girth weld with differentmismatch is assessed numerically by use of the fracturemechanics concept developed. The results show that type anddegree of mismatch have a great influence on the CCG behaviourand that C*alone cannot characterise crack tip fields.Corresponding R5 assessments are also performed. Comparisonwith the numerical investigation shows that the assumption ofplane stress or plane strain conditions in the R5 analysis isessential for the agreement of the results. Assuming the formerresults in a relatively good agreement for the axial stressdominated cases while for the hoop stress dominated cases, R5predicts higher CCG rates by an order of magnitude.
Keywords:ABAQUS, constraint effect, continuum damagemechanics, creep, creep crack growth, design, design code,finite element method, fracture mechanics, life assessment,mismatch, numerical simulation, weldment
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Hoang, Hue, and Matilda Widerström. "Simulation of distributed windings using the insert technique." Thesis, Högskolan i Skövde, Institutionen för ingenjörsvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-17430.
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During the insert process when the windings of an electric motor are pushed into the stator slots, some detrimental phenomena can occur that affect the efficiency and life of the motor. To detect these phenomena and optimize the process, a simulation would be useful. An investigation of the possibility to perform a simulation, using an appropriate numerical method for the insert process of distributed windings in a permanent magnet synchronous motor, was performed. During the project, a literature study was carried out to investigate existing methods and key-parameters for the simulation of the process. Explicit finite element method has been shown to be a suitable numerical method for simulating another winding process. An explicit finite element analysis was performed with a simplified model of the stator, the wires, the transmission tool and the needles by using the software Abaqus/CAE. In order to reduce the computational time, beam elements were used to model the wires and the other parts as rigid bodies. The model accounted for example contact and provided numerical results. The result was a suitable model. However, it needs to be developed further.
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Tao, Jiyue, and Asnaf Aziz. "Simulation of thermal stresses in a disc brake." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH. Forskningsmiljö Produktutveckling - Simulering och optimering, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-19163.
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The heat flux produced from the friction between a disc and pad system leads to a high temperature which causes thermal stresses in the disc and after a number of repeated braking cycles, cracks might be initiated. The finite element analysis (FEA) is performed to determine the temperatures profile in the disc and to analyze the stresses for the repeated braking, which could be used to calculate the fatigue life of a disc.Sequentially coupled approach is used for thermo-mechanical problem and the problem is divided into two parts, heat analysis and thermal stress analysis. The heat analysis is obtained by including frictional heat and adopting an Eulerian approach. The heat analysis is conducted by using Abaqus and the toolbox developed by Niclas Strömberg. The thermal stress analysis, which is the main focus of this thesis, is followed using Abaqus. The plasticity theory as background for stress analysis is discussed in detail. The rate independent elasto-plastic plasticity is used in the stress analysis. Temperature independent material properties are considered throughout the thesis work.Isotropic, kinematic and combined hardening models are analyzed for simple 2D academic models for different types of cyclic loads. A benchmark disc and pad model, which is less complicated than the real disc-pad model, is also studied. The linear kinematic hardening model with rate independent elastic-plastic plasticity is used for benchmark and real disc-pad model. The results of the benchmark model and the real model are observed to be similar in terms of plasticity theory.
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Ding, Chu. "Monotonic and Cyclic Simulation of Screw-Fastened Connections for Cold-Formed Steel Framing." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/55270.
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This thesis introduces an approach for modeling the monotonic and cyclic response of cold-formed steel framing screw-fastened connections in commercial finite element programs. The model proposed and verified herein lays the groundwork for seismic modeling of cold-formed steel (CFS) framing including shear walls, gravity walls, floor and roof diaphragms, and eventually whole building seismic analysis considering individual fastener behavior and CFS structural components modeled with thin-shell elements. An ABAQUS user element (UEL) is written and verified for a nonlinear hysteretic model that can simulate pinching and strength and stiffness degradation consistent with CFS screw-fastened connections. The user element is verified at the connection level, including complex cyclic deformation paths, by comparing to OpenSees connection simulation results. The connection model is employed in ABAQUS shear wall simulations of recent monotonic and cyclic experiments where each screw-fastened connection is represented as a UEL. The experimental and simulation results are consistent for shear wall load-deformation response and cyclic strength and stiffness degradation, confirming the validity of the UEL element and demonstrating that light
steel framing performance can be directly studied with simulations as an alternative to experiments.Master of Science
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Crudo, Cinzia. "Investigation on laser shock peening capability by FE simulation." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/5534/.
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Laser shock peening is a technique similar to shot peening that imparts compressive residual stresses in materials for improving fatigue resistance.
The ability to use a high energy laser pulse to generate shock waves, inducing a compressive residual stress field in metallic materials, has applications in multiple fields such as turbo-machinery, airframe structures, and medical appliances.
The transient nature of the LSP phenomenon and the high rate of the laser's dynamic make real time in-situ measurement of laser/material interaction very challenging.
For this reason and for the high cost of the experimental tests, reliable analytical methods for predicting detailed effects of LSP are needed to understand the potential of the process.
Aim of this work has been the prediction of residual stress field after Laser Peening process by means of Finite Element Modeling.
The work has been carried out in the Stress Methods department of Airbus Operations GmbH (Hamburg) and it includes investigation on compressive residual stresses induced by Laser Shock Peening, study on mesh sensitivity, optimization and tuning of the model by using physical and numerical parameters, validation of the model by comparing it with experimental results.
The model has been realized with Abaqus/Explicit commercial software starting from considerations done on previous works.
FE analyses are “Mesh Sensitive”: by increasing the number of elements and by decreasing their size, the software is able to probe even the details of the real phenomenon. However, these details, could be only an amplification of real phenomenon. For this reason it was necessary to optimize the mesh elements' size and number.
A new model has been created with a more fine mesh in the trough thickness direction because it is the most involved in the process deformations.
This increment of the global number of elements has been paid with an "in plane" size reduction of the elements far from the peened area in order to avoid too high computational costs.
Efficiency and stability of the analyses has been improved by using bulk viscosity coefficients, a merely numerical parameter available in Abaqus/Explicit.
A plastic rate sensitivity study has been also carried out and a new set of Johnson Cook's model coefficient has been chosen.
These investigations led to a more controllable and reliable model, valid even for more complex geometries.
Moreover the study about the material properties highlighted a gap of the model about the simulation of the surface conditions.
Modeling of the ablative layer employed during the real process has been used to fill this gap.
In the real process ablative layer is a super thin sheet of pure aluminum stuck on the masterpiece.
In the simulation it has been simply reproduced as a 100µm layer made by a material with a yield point of 10MPa.
All those new settings has been applied to a set of analyses made with different geometry models to verify the robustness of the model.
The calibration of the model with the experimental results was based on stress and displacement measurements carried out on the surface and in depth as well.
The good correlation between the simulation and experimental tests results proved this model to be reliable.
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Ashakul, Aphinat. "Finite Element Analysis of Single Plate Shear Connections." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/11192.
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There have been several design models for single plate shear connections in the past 20 years. The current design model states that the bolt shear rupture strength of a connection is a function of the number of bolts and the a-distance, which is the distance from the weld line to the bolt line. The evaluation of this design model demonstrates inconsistent predictions for the strength of the connection.
The finite element program ABAQUS was used throughout the research to study single plate shear connections. Finite element analyses included model verification and investigations of parameters, including the effect of a-distance, plate thickness, plate material, and the position of a connection with respect to a beam neutral axis. In addition, double-column bolt connections were studied.
The results show that bolt shear rupture strength of a connection is not a function of the a-distance. Plate materials and thicknesses that do not satisfy ductility criteria result in connections with significant horizontal forces at the bolts. This horizontal force reduces the shear strength of a bolt group and creates a moment that must be considered in design. The magnitude of the force depends on the location of the bolt with respect to the beam neutral axis. A new design model for single plate shear connections with bolts in a single column is proposed.
It was found that in double-column bolt connections, force redistribution among the bolt columns occurs. Force redistribution does not occur when thick plates are used, resulting in bolts in the outer column (from the support) fracturing while bolts in the inner column resist much less force. Further study is needed for double-column configurations.
The study of plate behavior shows that the shear stress distribution when a plate reaches the strain hardening stage is not constant throughout the cross section. A relationship for calculating plate shear yielding strength based on this shear distribution is proposed.Ph. D.
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Wollf, Cyprien. "Modélisation du processus thermo-électro-mécanique de frittage flash." Thesis, Metz, 2011. http://www.theses.fr/2011METZ018S/document.
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Le « Frittage Flash » ou « Spark Plasma Sintering (SPS) » est utilisé pour consolider des poudres en des temps relativement courts (quelques minutes). Ce procédé utilise un haut courant continu pulsé (quelques kA), traversant les parties conductrices du système et générant une montée rapide en température induite principalement par effet Joule. L’application d’un chargement mécanique, via des pistons, et d’une rapide montée en température permet d’obtenir une pièce dense sans grossissement excessif des grains. L’objectif de ce travail a été de proposer une simulation numérique thermo-électro-mécanique du procédé « Frittage Flash » sur ABAQUS, afin de suivre in situ les évolutions de température, de porosité et des contraintes difficilement accessibles expérimentalement. Dans ce travail, un modèle de comportement des corps poreux est proposé. Cette approche est basée sur les modèles micromécaniques de la littérature et modifiés de manière heuristique pour reproduire la densification réelle du matériau pour des porosités comprises entre 0 et 50%. Les simulations thermo-électro-mécanique incluant ce modèle, intègrent la dépendance en porosité et température des paramètres matériaux. Quatre cycles d’élaboration de poudre de nickel ont été réalisés avec différentes histoires de température. Les évolutions de la température et de la porosité calculées ont été confrontées avec des résultats expérimentaux. Des analyses post mortem sur des échantillons densifiés confortent la distribution de la température obtenue par le calcul. Ce travail ouvre de nombreuses perspectives, notamment, la possibilité d’optimiser le procédéNowadays, Spark Plasma Sintering (SPS) is used to consolidate powders in a relative short time (few minutes). This process uses a pulsed high DC electrical current (few kA) which flows through the conductive part of the device and generates large heating rate mainly due to Joule effect. The application of an uniaxial pressure via punches combined with a rapid heating allow the production of near net shape specimen. The thermal electrical mechanical numerical simulation of SPS process is a powerful tool to capture in situ evolutions of temperature, porosity and stresses which are difficult to obtain in experiments. In this work, a new constitutive model is presented for the description of the behavior of porous medium. This model is based on original viscoplastic micromechanical models of the literature and modified in a heuristic manner to better reproduce the real densification of sintered material for porosity in the range [0;0,5]. The model has been implemented in ABAQUS software. A thermal electrical mechanical simulation of SPS is performed where the dependence of material parameters on temperature and porosity is taken into account. Four processing cycles of nickel have been conducted with different temperature histories. Calculated porosity and temperature evolutions are compared to experimental results. Post-mortem analyses of the material (grain size, yield stress) confirm the temperature distribution obtained by numerical simulations in the sample made of nickel. This simulation is seen to be able to capture experimental trends. The work will permit in a near future the optimization of the sintering conditions to reach prescribed properties
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Abdullah, Ahmad Sufian. "Crash simulation of fibre metal laminate fuselage." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/crash-simulation-of-fibre-metal-laminate-fuselage(fd254489-243f-4071-8dea-ca9e2dd9d3bc).html.
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A finite element model of fibre metal laminate (FML) fuselage was developed in order to evaluate its impact response under survivable crash event. To create a reliable crash finite element (FE) model of FML fuselage, a ‘building block approach’ is adapted. It involves a series of validation and verification tasks in order to establish reliable material and damage models, verified impact model with structural instability and large displacement and verified individual fuselage structure under crash event. This novel development methodology successfully produced an FE model to simulate crash of both aluminium alloy and FML fuselage under survivable crash event using ABAQUS/Explicit. On the other hand, this allows the author to have privilege to evaluate crashworthiness of fuselage that implements FML fuselage skin for the whole fuselage section for the first time in aircraft research field and industry. The FE models consist of a two station fuselage section with one meter longitudinal length which is based on commercial Boeing 737 aircraft. For FML fuselage, the classical aluminium alloy skin was replaced by GLARE grade 5-2/1. The impact response of both fuselages was compared to each other and the results were discussed in terms of energy dissipation, crushing distance, failure modes, failure mechanisms and acceleration response at floor-level. Overall, it was observed that FML fuselage responded similarly to aluminium alloy fuselage with some minor differences which conclusively gives great confidence to aircraft designer to use FML as fuselage skin for the whole fuselage section. In terms of crushing distance, FML fuselage skin contributed to the failure mechanisms of the fuselage section that lead to higher crushing distance than in aluminium alloy fuselage. The existence of various failure modes within FML caused slight differences from the aluminium fuselage in terms of deformation process and energy dissipation. These complex failure modes could potentially be manipulated to produce future aircraft structure with better crashworthiness performance.
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Cravotta, Stefan, and Emanuele Grimolizzi. "Simulation of vehicle impact into a steel building : A parametric study on the impacted column end-connections." Thesis, KTH, Bro- och stålbyggnad, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-172341.
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Understanding the true behaviour of impacted structures is the only way to assess their robustness under exceptional events such as vehicle collision. The primary objective of this master’s thesis was to perform a finite element parametric investigation on the influence that some parameters have in steel buildings subjected to vehicle impacts. The parameters chosen for the study, involved uncertainties in the material definition and in the load configuration of the bolts used in the impacted column end-connections. By using the Abaqus software, a finite element model of the structure has been created. The five storey steel building considered has been modelled in a simplified manner with the exception of the impacted area which, instead, has been defined in a more detailed fashion. During the simulations, different preload conditions have been used, comparing cases with and without the preload force. Regardless its variation, it has not been observed any increase in the structural resistance. On the other hand, the simulation provided interesting results for what concerns the material variations in the bolts. Although the changes have been small in magnitude, the effect on the structural response during the impact was remarkable. For all the cases considered, an increase of the material ductility, achieved by increasing the ultimate strain at failure, entailed higher resistance of the connections. Various failure modes have been observed when the material properties have been changed. Having clarified the influence of the assumptions made, the results provided helpful information in sight of future studies. Although the model still needs to be validated, the research clarified which of the parameters investigated are to be collected with more attention. Keywords: Vehicle collision, steel building, FE model, Abaqus/Explicit, parametric investigation, bolt preload, bolt material.
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Bressan, Caroline Zanini. "Estudo numérico dos ensaios de tração simples e flexão de três pontos do aço livre de interstícios (IF) utilizando o modelo de Gurson modificado." Universidade do Estado de Santa Catarina, 2015. http://tede.udesc.br/handle/handle/2066.
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Numerical methods have received a substantial attention from Engineering Professionals especially due their capacity to provide solutions for a wide range of problems in many areas. In the last years, numerical simulation has become increasingly common and has turned into a key factor for solving numerous engineering problems in the industry as well in academia. This, however, requires the development of suitable methodological strategies to determinate constitutive law able to best describe the material behavior in the simulation. The present work is inserted within the context of metal forming, aiming to simulate 2D and 3D geometrical models of the simple tensile test and three-point bending test of a notched plate, both using the material properties of an Interstitial Free Steel, IF. For both cases, it was used a modified Gurson model available in the ABAQUS ® software, which is based on the finite elements method. Numerical modelling of the elasto-plastic process used to simulate the three-point bending and simple tensile test was discretised using structured meshes with an appropriate refinement. The experimental results for tensile tests used smooth cylindrical specimens with dimensions defined according to ASTM E 8M-01. The three point bending test was qualitatively compared with the results reported by Mashayeshi, et al (MASHAYEKHI, ZIAEI-RAD, et al., 2005). The strain hardening law used in this work was the Holomon or modified Swift law coupled with the damage evolution of the Gurson s model. The geometrical models for the tensile specimens account for axisymmetry, so that only one-quarter part of the 2D and 3D specimens was modelled. An appropriate mesh refinement in the necking region was also adopted. The numerical simulation was able to predict with success the stress-strain curve behaviour of the IF steel comparing with the experimental results. Both 2D and 3D simulation results of the simple tensile test were very similar. The prediction of porosity evolution with the applied displacement was analysed and the results indicated that the necking region in the central zone of the specimen presented the largest micro-void concentration, as expected. For the three-point bending test of a notched plate, the simulation provided a good qualitative agreement with the Mashayekhi´s numerical results, which have shown that the largest concentration of micro-voids was in the central region of the notch where the crack initiation occurs.
Métodos numéricos tem recebido uma grande atenção dos profissionais da área da engenharia em especial principalmente pelo seu caráter facilitador na solução de problemas em diversas áreas. Nos últimos tempos, a simulação numérica está se tornando cada vez mais comum e se transformando em uma peça chave para a resolução de inúmeros problemas de engenharia encontrados tanto nas indústrias quanto nas linhas de pesquisa científica das universidades. Isso, porém, exige desenvolvimento de estratégias de metodologias científicas adequadas o suficiente para determinar as leis que descrevam melhor o comportamento dos materiais a serem simulados. O presente trabalho está inserido no contexto da conformação de metais, tendo por objetivo simular, com malhas tipo 2D e 3D, os ensaios de tração simples e de flexão de três pontos de uma placa com entalhe de um aço livre de interstícios, aço IF (interstitial free steel), utilizando o modelo de Gurson modificado no programa ABAQUS ®, que utiliza o Método dos Elementos Finitos. Para o modelamento numérico do processo de deformação elasto-plástica dos ensaios de tração simples e flexão foi utilizada a lei de Gurson modificado de materiais porosos e uma malha com refinamento adequado. Os corpos de prova ensaiados experimentalmente em tração simples foram de aço IF cilíndricos preparados de acordo com a norma ASTM E 8M-01. Já o ensaio de flexão de três pontos foi simulado com o intuito de fazer uma comparação qualitativa com o resultado apresentado por Mashayekhi, Ziaei-Rad, et al. (MASHAYEKHI, ZIAEI-RAD, et al., 2005). A lei de encruamento plástico utilizada neste trabalho foi a Lei de Holomon ou Swift modificado acoplado com o modelo de evolução do dano de Gurson modificado. Após a escolha da geometria de somente quarta parte do corpo de prova, devido à simetria axissimétrica e do refinamento adequado da malha na região da estricção local, a simulação numérica foi capaz de prever com sucesso o comportamento da curva de tensãodeformação do aço IF comparando-se com os resultados experimentais. Os resultados da simulação 2D e 3D do ensaio de tração simples foram iguais. Portanto, a simulação 2D do ensaio de tração simples é mais conveniente pois é mais rápida e igualmente precisa que a simulação 3D para o presente caso de material dúctil e isotrópico. A previsão da evolução da porosidade com a deformação e a região de maior concentração de vazios foi analisada: ocorreu na região da estricção local e na zona central do corpo de prova como esperado. No caso do ensaio de flexão da placa com entalhe central, os resultados da simulação numérica mostraram uma boa concordância com os resultados de Mashayekhi, Ziaei-Rad et al. (2005), que apresentaram a maior concentração de vazios na região central do entalhe onde ocorrerá o aparecimento de trincas.
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Reul, Stefan. "Simulation von Lagern - Vergleiche -." Universitätsbibliothek Chemnitz, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200900796.
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- Allgemeine Problematik bei der FEM-Simulation von Lagern/Gelenken
- Modellierungstechniken in MECHANICA wie z.B. Kontakt-Analysen, Balkenspinnen, gewichtete Verbindungen, orthotropes Material, etc.
- Vergleich dieser Techniken und Diskussion der Vor- und Nachteile anhand eines Gleitlagers
- Empfehlungen und Regeln
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Kuai, Le. "Parametrized Finite Element Simulation of Multi-Storey Timber Structures." Thesis, Linnéuniversitetet, Institutionen för skog och träteknik (SOT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-66825.
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With the acceleration of global urbanization trends, more and more intentions are put on multi-storey buildings. As the world leading area of wood construction, European countries started the construction of multi-storey timber building for a decade ago. However, unlike the traditional buildings made of reinforced concrete, the design of wooden high-rise timber buildings would face a substantial amount of new challenges because such high-rise timber buildings are touching the limitations of the timber engineering field. In this thesis, a parameterized three-dimensional FE-model (in ABAQUS) of a multi-storey timber frame building is created. Variable geometrical parameters, connection stiffness as well as boundary connections and applied wind and gravity loads are defined in a Python script to make it possible to analyze the influence of these parameters on the global structural behavior of the studied multi-storey timber frame building. The results and analysis implied that the script successfully worked and was capable to create different complex building geometries in an wasy way for the finite element analysis.
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Barbosa, Catarina de Lemos Grilo Ferreira. "Modelling metal punching using ductile failure criteria." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/14422.
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Mestrado em Engenharia MecânicaDuring the process of mechanical conforming of metal sheet by punching process, several factors influence the accuracy and final geometry of the hole punched. The properties of material used and its behavior in the face of imposed deformations, as well as process parameters influence the final result. High Strength Low Alloy steels (HSLA) are particularly suitable for structural parts that do not require severe forming, such as industrial shelving systems or furniture. Knowledge of mechanical punching operation is of utmost importance to planners of product, process and tooling, so you can get quality products at an acceptable level of waste. The numerical simulation can contribute significantly to the prediction of behavior, still in the planning phase of the product. The goal of this paper is analyze the influence of gap between punch and die during punching. The metal plate material was used with a thickness of 8mm DIN EN 10268 H 360 LA with gaps between punch and die ranging from 2% to 10%. For this we developed a 2D axisymmetric model in ABAQUS/Explicit software, Version 6.7 and the result were compared with literature data and practical experiment. Test showed that the gap of 2% showed the best result..
Durante o processo de conformação metálica por embutidura vários fatores influenciam na geometria final do puncionado. As propriedades do material usado e o seu comportamento perante conformações impostas, assim como característica do processo comprometem o resultado final. Aços HSLA são particularmente apropriado para componentes estruturais que não requerem conformação profunda, tal como os usados na industria de mobiliário metálico. Conhecimento em operações de embutidura mecânica é de maior importância para gestores de produto, processo e ferramentas, para obtenção de produtos de elevada qualidade e desperdício mínimo. A simulação numérica contribui significativamente para a previsão do comportamento ainda na fase de planeamento. O objetivo deste trabalho é analisar a influência da distância entre o punção e a matriz. Considerou-se uma variação entre 2 a 10% nesta análise. Para cumprir estes objetivos criou-se um modelo axissimetrico 2D no ABAQUS/Explicit Software versão 6.7 e o resultado foi comparado com dados bibliográficos e ensaios laboratoriais. Testes demonstraram que a distância entre o punção e a matriz de 2% proporciona o melhor resultado.
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Tucci, Fausto. "Modelling and numerical simulation of pultrusion processes." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/21263.
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Mestrado em Engenharia MecânicaO objectivo deste trabalho prende-se com a modelação e análise por simulação numérica, através do Método dos Elementos Finitos, da distribuição de temperaturas (e sua evolução) durante reações de polimerização das resinas em compósitos sujeitos a processos de pultrusão. A modelação baseou-se numa abordagem quasi-estática num enquadramento tridimensional e a partir de pressupostos de base Eulerianos para as equações de evolução. A um modelo inicial termo-químico foi acoplado um modelo mecânico de equilíbrio, por forma a estimar por meio de simulação numérica o perfil das tensões decorrentes do processo de conformação, bem como as deformações associadas. A implementação do modelo numérico por elementos finitos foi realizada através da utilização do programa comercial ABAQUS, por meio do desenvolvimento de uma série de subrotinas de utilizador (em linguagem Fortran) desenvolvidas pelo autor deste trabalho.
The focus of this work is the implementation of a Finite Element model for the simulation of temperature distributions and evolutions during the exothermic reaction of polymerization of resins in pultrusion processes. The problem has been modelled using a quasi-static approach in a three-dimensional Eulerian domain. To the thermochemical model it was sequentially coupled the resolution of typical mechanical balance equations, in order to numerically estimate the stress levels within the material and the corresponding strains. The implementation of the numerical finite element model was carried out using the ABAQUS finite element software, by means of a number of user subroutines (in Fortran language) implemented by the author.
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Hu, Tianmeng. "Modélisation géomécanique des réservoirs : méthodologies de mise en œuvre et d'analyse des incertitudes." Thesis, Vandoeuvre-les-Nancy, INPL, 2008. http://www.theses.fr/2008INPL059N/document.
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L’objectif de ce travail est double : d’une part, il s’agit de développer une méthodologie intégrée pour la construction d’un modèle géomécanique ainsi que la représentation des incertitudes associées aux propriétés poro-élastiques des roches constitutives, en exploitant l’ensemble des données disponibles et en s’appuyant de façon cohérente sur les modèles de réservoir statique et dynamique classiquement utilisés par les géologues et les ingénieurs réservoir ; d’autre part, il s’agit d’analyser quel est l’impact des hétérogénéités géologiques, souvent négligées, dans la réponse mécanique du réservoir sollicité par son exploitation, et d’aboutir à des incertitudes sur les champs de contraintes et de déplacements, issues des incertitudes sur ces hétérogénéités et leurs paramètres mécaniques. Pour ce faire, une méthodologie intégrée s’appuyant sur des simulations géostatistiques a été développée. Après la construction du cadre géométrique 3D, le remplissage des propriétés au sein du réservoir suit une démarche de simulations géostatistiques 3D emboîtées, dans laquelle la représentation des hétérogénéités lithologiques conditionne la génération des propriétés poro-élastiques. La démarche consiste ensuite à représenter les incertitudes sur le modèle géomécanique par des ensembles de réalisations géostatistiques dont la réponse mécanique est alors calculée avec un simulateur mécanique aux éléments finis. Les incertitudes sur les champs de contraintes et de déformations sont déduites ensuite des différentes réponses mécaniques obtenues. La démarche a été mise en œuvre sur un réservoir réel, dans un environnement fluvio-deltaïque, produisant en Mer du Nord. Dans ce cadre, il a été démontré que les hétérogénéités du réservoir et leurs incertitudes influencent significativement les calculs des champs de contraintes et de déformations, ainsi que les risques mécaniques de rupture. Des incertitudes sur les quantités mécaniques analysées (premier invariant du tenseur des contraintes et subsidence) ont été aussi estiméesThis work has two main objectives. The first one is to develop an integrated methodology allowing to build a 3D geomechanical model and also to image the uncertainties attached to the poro-mechanical properties of the constitutive rocks. This geomechanical model should be based on all related available data and should be consistent with the static and dynamic models, currently built by reservoir geologists and engineers. The second objective is to analyse the impact of geological heterogeneities, which are often neglected, in the mechanical response of the reservoir induced by its exploitation, and furthermore to derive uncertainties on the stress and deformation fields related to the uncertainties on the input properties of the geomechanical model. An integrated methodology based on geostatistical simulations is developed. First, the geometric frame is built; then an approach of embedded stochastic simulations is carried out to infill the different reservoir properties, the lithological description constraining the petrophysical and poro-elastic descriptions. The next step is to generate the mechanical responses of the stochastic realisations, using a finite-element mechanical simulator. The uncertainties on the resulting stress and displacement fields are then deduced from the multiple mechanical responses which are computed. This approach is demonstrated on a real field case, a fluvio-deltaic reservoir in North Sea. It is shown on this example that the reservoir heterogeneities and their uncertainties significantly influence the calculations of stress and strain fields, and also the risks of mechanical failure. Uncertainties on the mechanical quantities under analysis (first invariant of the stress tensor and subsidence) are also derived
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James, Aricatt John, and Devarajan Velmurugan. "Determination of stresses and forces acting on a Granulator knife by using FE simulation." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH. Forskningsmiljö Produktutveckling - Simulering och optimering, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-28297.
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Recycling of plastics always plays an important role in keeping our environment better and safe. With the rise in usage of plastics and industrialization, the need for recycling the plastics has become a big business and is getting bigger. This thesis work was done for a company called Rapid Granulator AB, which works with the recycling of plastics as a big trade in Sweden. Like all the industries across the globe are trying to be economical in every way, Rapid Granulator AB wanted to develop an economical design of their high quality granulating knife. For achieving the economical design, they wanted to study the behaviour of the rotating knife during the process of producing plastic granules. The granulator cutting process was simulated and numerical analysis was done on the rotating knife of a plastic granulator machine by using the finite element code ABAQUS with 3D stress elements to find out the critical stresses and forces acting on the rotating knife. The bolt preload was applied by Abaqus/Standard, and the results of implicit analysis were imported to Abaqus/Explicit for the impact analysis where the flow of stresses on the rotating knife during the impact with materials were simulated and studied. The study was done on knife models of different thickness to see if the thickness of the current knife model can be reduced. Analysis were done also on a knife model assembly with a double sided cutting edge knife to see if the knife model can be used to its full extent. The simulation models and analysis results were given to the company to develop a more economical knife model.
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Rolseth, Anton, and Anton Gustafsson. "Implementation of thermomechanical laser welding simulation : Predicting displacements of fusing A AISI304 T-JOINT." Thesis, Högskolan i Skövde, Institutionen för ingenjörsvetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-19946.
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Laser welding is an advanced joining technique with the capability to form deep, narrow, and precise welds. Numerical models are used to simulate the process in attempts of predicting distortions and stresses in the material. This is done to reduce physical testing, optimize processes and enable integrated product- and process development. The Virtual Manufacturing Process research group at University of Skövde wishes to increase their knowledge on modeling options of thermomechanical simulations to grant local industries these benefits. A numerical model for the laser welding process was developed in ABAQUS. This was done by examining the macrograph structure of a simple weld and applied to a stainless-steel T-joint welding application. The macrograph data was used to calibrate a mathematical heat source model. User subroutine DFLUX was used to enable movement of the heat source and element activation was used to simulate the fusion of the two parts. A T-joint welding experiment was carried out to measure deflection and the result was compared to numerical simulations. Different combinations of heat source models, coupling type and element activation was compared in relation to predicting the deflection. Computational time and modeling complexity for the techniques was also considered.The results showed that a 3D Gaussian heat source model will imitate the keyhole weld achieved superior to the compared 2D model. The 3D model provides greater flexibility since it enables combinations of any geometrical bodies. It was shown that element activation has a significant contribution on part stiffness and thus resulting distortions. To implement element activation a fully coupled analysis is required. The deflection of the fully coupled 3D simulation with element activation showed a 9% deviance in deflection compared with experiments.
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Lora, Ruben, and Jayesh Namjoshi. "Simulation of Residual Stresses in Castings." Thesis, Jönköping University, JTH, Mechanical Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-1587.
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This work presents a study and implementation of the simulation of residual stresses in castings. The objects of study are a cast iron truck Hub part (provided by the company Volvo 3P) and an optimized version of the Hub resulting from the application of a topology optimization process. The models are solved through an uncoupled thermo-mechanical solidification analysis, performed both in the FE commercial software Abaqus and the FD commercial software Magmasoft and the results are compared. First, a thermal analysis is carried out where the casting is cooled down from a super-heated temperature to room temperature. The thermal history obtained, is then used as an external force to calculate the residual stresses by means of a quasi-static mechanical analysis, using a J2-plasticity model. The simulation procedures are explained through a simplified model of the Hub and then applied to the geometries of interest. A results comparison between the original Hub and its optimized version is also presented. The theoretical base is given in this work as well as detailed implementation procedures. The results shows that the part subjected to the topology optimization process develop less residual stresses than its original version.
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Andersson, Robin, and Robert Timalm. "Development and simulation of a safety bracket for a safety system." Thesis, Tekniska Högskolan, Jönköping University, JTH, Industriell produktutveckling, produktion och design, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-49324.
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This thesis report aims to help the client developing their new product. The new product to be developed is a safety bracket for a safety system. The safety bracket connects different parts which create the safety system and it should be able to withstand impacts from moving objects. The client has a set of requirements that needs to be addressed during the product development process. One of the most important requirements that must be fulfilled is the given impact energy that the safety bracket must withstand. The methodology used during this thesis work is the product development processes (PDP). The product development process is used to find concepts that have the potential to answer the research questions and to fulfil the requirements. Some methods used in the product development process are brainstorming, brainwriting and combining working principles. The concepts were evaluated with a combination of Pugh´s matrix and weighting matrix. The three best concepts were selected for further development and tested with FEA simulation with Abaqus CAE. The impact simulation gave indications if the concepts could handle the impact energy and if they could fulfil the requirements. All three concepts could withstand the impact energy based on the simulations and most of the requirements could be fulfilled. The concepts with thinner profile walls had a reduction in stress and an increase in impact duration, where the kinetic energy is distributed throughout the impact. A protective shell helps with the reduction of stress and the energy absorption during the impact simulation.
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Brennen, Peter Alexander. "SIMULATION OF AN OXIDIZER-COOLED HYBRID ROCKET THROAT: METHODOLOGY VALIDATION FOR DESIGN OF A COOLED AEROSPIKE NOZZLE." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/166.
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A study was undertaken to create a finite element model of a cooled throat converging/diverging rocket nozzle to be used as a tool in designing a cooled aerospike nozzle. Using ABAQUS, a simplified 2D axisymmetric model was created featuring only the copper throat and stainless steel support ring, which were brazed together for the experimental test firings. This analysis was a sequentially coupled thermal/mechanical model. The steady state thermal data matched closely to experimental data. The subsequent mechanical model predicted a life of over 300 cycles using the Manson-Halford fatigue life criteria. A mesh convergence study was performed to establish solution mesh independence.
This model was expanded by adding the remainder of the parts of the nozzle aft of the rocket motor so as to attempt to match the transient nature of the experimental data. This model included variable hot gas side coefficients in the nozzle calculated using the Bartz coefficients and mapped onto the surface of the model using a FORTRAN subroutine. Additionally, contact resistances were accounted for between the additional parts. The results from the preliminary run suggested the need for a parameter re-evaluation for cold side gas conditions. Parametric studies were performed on contact resistance and cold side film coefficient. This data led to the final thermal contact conductance of k=0.005 BTU/s•in.•°R for contact between metals, k=0.001 BTU/s•in.•°R for contact between graphite and metal, and h=0.03235 BTU/s2•in.•°R for the cold side film coefficient. The transient curves matched closely and the results were judged acceptable.
Finally, a 3D sector model was created using identical parameters as the 2D model except that a variable cold side film condition was added. Instead of modeling a symmetric one or two inlet/one or two outlet cooling channel, this modeled a one inlet/one outlet nozzle in which the coolant traveled almost the full 360° around the cooling annulus. To simplify the initial simulation, the model was cut at the barrier between inlet and outlet to form one large sector, rather than account for thermal gradients across this barrier. This simplified nozzle produced expected data, and a 3D full nozzle model was created. The cold side film coefficients were calculated from previous experimental data using a simplified 2D finite difference approach. The full nozzle model was created in the same manner as the 2D full nozzle model. A mesh convergence study was performed to establish solution mesh independence. The 3D model results matched well to experimental data, and the model was considered a useful tool for the design of an oxidizer cooled aerospike nozzle.
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Pacheco, Roman Oscar. "Evaluation of Finite Element simulation methods for High Cycle Fatigue on engine components." Thesis, Linköpings universitet, Mekanik och hållfasthetslära, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-148779.
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This document reflects the results of evaluating three computational methods to analyse the fatigue life of components mounted on the cylinder block; two currently in use at Scania and one that has been further developed from its previous state. Due to the cost of testing and the exponential increase in computational power throughout the years, the cheaper computational analyses have gained in popularity. When a component is mounted in a fairly complex assembly such as an engine, simplifications need to be made in order to make the analysis as less expensive as possible while keeping a high degree of accuracy. The methods of Virtual Vibrations, VROM and VFEM have been evaluated and compared in terms of accuracy, computational cost, user friendliness and general capacities. Additionally, the method VFEM has been further developed and improved from its previous state. A in-depth investigation regarding the differences of the methods has been conducted and improvements to make them more efficient are suggested herein. The reader can also find a decision matrix and recommendations regarding which method to use depending on the general characteristics of the component of interest and other factors. Two components, which differ in complexity and mounting nature, have been used to do the research.
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Fernandes, Felipi Pablo Damasceno. "Análise numérica de vigas mistas de madeira e concreto em situação de incêndio." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-18062018-120514/.
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As vigas mistas de madeira e concreto são formadas pela união de vigas de madeira a lajes de concreto armado por meio de conectores de cisalhamento. Quando os pisos mistos de madeira e concreto são comparados aos pisos construídos unicamente em madeira ou àqueles confeccionados somente em concreto armado é possível destacar algumas vantagens, incluindo o bom desempenho em situações de incêndio. Os elementos estruturais quando submetidos a ações térmicas sofrem redução de resistência e rigidez, sendo, desta forma, necessário conhecer as modificações sofridas por cada um de seus componentes, que para o caso estudado são: a madeira, o concreto e os conectores de cisalhamento. Desta forma, foi elaborada uma estratégia de modelagem numérica para o estudo de vigas mistas de madeira e concreto em situação de incêndio, utilizando o programa computacional ABAQUS, o qual é baseado no método dos elementos finitos. Em uma primeira etapa da pesquisa foram realizadas modelagens numéricas de vigas de madeira e mistas de madeira e concreto em temperatura ambiente, encontrando-se boa correlação entre as curvas força versus deslocamento no meio do vão obtida numericamente e por meio de ensaios disponíveis na literatura. Em seguida procedeu-se a calibração das propriedades térmicas e mecânicas da madeira brasileira, alcançando-se resultados numéricos próximos aos experimentais, seja em relação às temperaturas do elemento analisado seja em relação à curva de deslocamento vertical em função do tempo de incêndio. Por fim, a estratégia de modelagem termoestrutural desenvolvida para a viga mista de madeira e concreto forneceu curva de deslocamento vertical em função do tempo de incêndio semelhante à curva obtida por meio de modelo analítico disponível na literatura. Por meio do modelo elaborado foi possível observar que a elevação do nível de carregamento reduz o tempo de resistência do elemento estrutural e que a proteção térmica do concreto é essencial para aumentar o tempo até a ruptura da viga.Timber-concrete composite beams are formed by the union of timber beams to reinforced concrete slabs through of shear connectors. When timber-concrete composite floors are compared to timber floors or reinforced concrete floors it is possible to highlight some advantages, including good performance in fire situations. When subjected to thermal actions, structural elements suffer strength and stiffness reductions, being, therefore, necessary to know the modifications suffered by each of its components, which for the case studied are: timber, concrete and shear connectors. Thus, it is developed a numerical modeling strategy using the computational program ABAQUS, which is based on the finite element method, for the study of timber-concrete composite beams in fire situation. In the first stage of the research it was carried out a numerical modeling of timber beam and timber-concrete composite beam at room temperature, finding good correlation between the force versus displacement curves in the middle of the span obtained numerically and through tests available in the literature. Then, it was carried out the calibration of the thermal and mechanical properties of the Brazilian wood, reaching numerical results close to the experimental ones, either in relation to the temperatures of the analyzed element or in relation to the vertical displacement curve as a function of the fire time. Finally, the thermo-structural modeling strategy developed for the timber-concrete composite beam provided a vertical displacement curve as a function of the fire time similar to the curve obtained through an analytical model available in the literature. Through of the elaborated model it was possible to observe that the load level increase reduces the resistance fire time of the structural element and that the thermal protection of the concrete is essential to increase the rupture time of the beam.
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Amini, Khoiy Keyvan. "Biomechanical Characterization and Simulation of the Tricuspid Valve." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1542651986497595.
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Kpenyigba, Kokouvi Mawuli. "Étude du comportement dynamique et modélisation thermoviscoplastique de nuances d'acier soumises à un impact balistique." Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0272/document.
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Ce travail de thèse a pour but de contribuer à l'étude du comportement thermomécanique des matériaux métalliques soumis à un impact balistique. Des études expérimentales, analytiques et numériques ont été réalisées pour analyser en détail le processus de perforation. Deux matériaux ont été étudiés au cours de ce travail : un acier doux ES et un acier IF. Dans un premier temps, des essais de caractérisation mécanique (traction et compression quasi-statique et dynamique) ont été réalisés en vue de la modélisation du comportement mécanique des matériaux étudiés. Les résultats montrent que l'acier doux ES et l'acier IF sont très sensibles à la vitesse de déformation. Deux modèles constitutifs, l'un empirique (Johnson-Cook) et l'autre semi-physique (Rusinek-Klepaczko) ont été utilisés pour modéliser le comportement thermoviscoplastique des matériaux. Une identification complète des constantes définissant les deux modèles a été réalisée pour chaque matériau en vue de l'implémentation des lois dans un code éléments finis pour la simulation numérique des essais d'impact et de perforation. Le comportement à l'impact des matériaux a ensuite été étudié. Les essais d'impact et de perforation ont été réalisés à l'aide d'un canon à gaz. L'influence de la géométrie du projectile, des propriétés mécaniques du matériau le constituant, de l'épaisseur de la cible et de sa configuration (sandwich ou monolithique) sur le processus de perforation a été analysée. Les résultats montrent que le mode de rupture, la limite balistique et la capacité d'absorption d'énergie de la cible métallique sont fortement liés à la forme du projectile utilisé. Il a été montré que les cibles métalliques monolithiques résistent mieux à la perforation que les configurations sandwichs (épaisseur totale inférieure ou égale à 4 mm). En outre, il a été trouvé que la limite balistique de la cible est fortement influencée par la rigidité du projectile utilisé. Enfin un modèle EF 3D a été développé permettant de simuler le comportement mécanique des cibles métalliques soumises à l'impact et à la perforation. Les résultats issus des prévisions numériques ont été comparés aux résultats expérimentaux. Il a été observé de façon globale un bon accord entre les prévisions numériques et l'expérience notamment en termes de courbes balistiques, d'énergie absorbée, de modes de rupture et de temps de rupture pour chaque type de projectile. Les résultats numériques montrent l'importance d'une description précise du comportement des matériaux dans les conditions dynamiques basée sur des expériences de laboratoire incluant les effets d'adoucissement thermique, d'écrouissage et de sensibilité à la vitesse de déformation, dans la modélisation numérique de processus physiquesThis thesis aims to contribute to the study of the thermo-mechanical behaviour of metallic materials subjected to ballistic impact. Experimental, analytical and numerical studies were performed to analyze in details the process of perforation. Two materials have been investigated in this work : mild steel ES and IF steel. As a first step, mechanical characterization tests (tensile and compression tests under quasi-static and dynamic conditions) As have been made towards to modeling the mechanical behaviour of the materials studied. The results show that mild steel ES and IF steel are highly susceptible to the strain rate. Two constitutive equations, one empirical (Johnson-Cook) and other semi-physical (Rusinek-Klepaczko) were used to model the thermoviscoplastic behaviour of materials. A complete identification of constants defining the two models was carried out for each material in order to implements the constitutive laws into a finite element code for the numerical simulation of impact and perforation tests. The behaviour of materials under impact was then examined. The effect of the projectile shape, the mechanical properties of the projectile material, the target thickness and it is configuration (monolithic or sandwich) on the perforation process was analyzed. The results show that the failure mode, the ballistic limit and the energy absorption power of the metal target are strongly related to the shape of the projectile used. It has been shown that the monolithic targets plates are more strong to be perforate than the sandwich configurations (total thickness less than or equal to 4 mm). In addition, it was found that the ballistic limit of the target is strongly influenced by the rigidity of the projectile used. Finally, a 3D FE model was developed to simulate the mechanical behaviour of metal targets subjected to ballistic impact. The results from the numerical predictions were compared with experiments. It has been observed globally a good agreement between the numerical predictions and experiments especially in terms of ballistic curves, energy absorbed, failure modes and failure time for each kind of projectile. The numerical results show the importance of an accurate description of materials behaviour under dynamic conditions based on laboratory experiments including thermal softening effects, strain hardening and strain rate sensitivity in numerical modeling of physical processes
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Zetterberg, Mikaela. "A critical overview of machining simulations in ABAQUS." Thesis, KTH, Hållfasthetslära (Inst.), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-176396.
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Metal cutting is one of the most commonly occurring manufacturing processes in the industry and major effort is made to improve its processes. Cutting tools are expensive and have a life length measured in minutes, why predictions of tool wear are of great interest. Finite Element (FE) simulations have a central role in the development of tools and cutting processes, but performing simulations of metal cutting is not easy. The method chosen for the chip formation has a large impact on the result of the simulations. The scope of this work includes a survey on important parameters and different possibilities to form a chip in simulations of metal cutting in ABAQUS/Explicit. Particular emphases are placed the on prediction of flank wear and how the hardening implemented in the material model effects this. The approach has been to start with a literature study and thereafter make simulations in ABAQUS/Explicit. FE simulations, of cutting, with different damage criteria and simulations with SPH (Smooth Particle Hydrodynamics)- method are presented. None of the possibilities to form a chip in ABAQUS/Explicit, as implemented today, seems to be sufficient for simulations of cutting to predict flank wear. The SPH-method will be a good alternative for simulations of metal cutting in ABAQUS/Explicit if temperature dependency is implemented. The material model in general, the type of hardening in specific, has an impact on the chip-form and the stress state in the chip and workpiece. And thereby effects the flank wear.Skärande bearbetning är en av de vanligast förekommande tillverkningsprocesserna i industrin idag och mycket möda läggs ned för att förbättra dess processer. Skären är dyra och har en livslängd som kan mätas i minuter, vilket gör att möjligheten att förstå och förutsäga nötningen av skäret är av stort intresse. Finita element (FE) simuleringar har en central roll i utvecklingen av skärverktyg och skär processer, men att genomföra simuleringar av detta är långt ifrån enkelt. Metoden som väljs, för att forma en spåna har stor påverkan på resultatet av simuleringarna. Detta arbete innefattar en utredning kring viktiga parametrar och olika möjligheter att åstadkomma spånformning vid simuleringar av skärande bearbetning i ABAQUS/Explicit. Särskiljt har fokus legat på att kunna förutsäga nötning på skärets släppsida och hur hårdnandet, som finns implementerat i materialmodellen, påverkar denna. Angreppssättet har varit att starta med en litteraturstudie och därefter göra simulationer i ABAQUS/Explicit. Resultat från FE simuleringar, av skärande bearbetning, med olika brottvillkor och simuleringar med Smooth Particle Hydrodynamics (SPH)- metoden finns presenterade. Ingen av möjligheterna för spånformning som finns implementerade i ABAQUS/Explicit idag är tillräckligt bra för att simulera nötning av skärets släppsida. SPH-metoden kan komma att bli ett bra alternativ för simuleringar av skärande bearbetning i ABAQUS/Explicit om temperaturberoendet blir implementerat. Materialmodellen, och mer specifikt typen av hårdnande, påverkar spånformen och spänningstillståndet i spånan och arbetsstycket. Därmed påverkas också nötningen av skäret.
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Scalone, Santiago Andres. "A numerical evaluation of mode I & II damage propagation in composite materials." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15914/.
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A full numerical evaluation using Abaqus has been done for 2D and 3D Mode I and II delamination propagation (in composite materials). First the theory to explain all the mechanisms that are involved in delamination growth were developed, also the theory that Abaqus uses to solve the delamination process was explained. Furthermore, all the values that have been used were explained in detail, these values are difficult to find. Then, the results were obtained combining the delamination theory with Matlab. The parameters that have been analyzed are: critical strain energy release rate, the most relevant stresses around the delamination and the shape of the delamination tip. The numerical results are in accordance with the experimental results, thus, the simulations are able to predict the delamination growth.
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Sow, Libasse. "Approche couplée expérimentation - modélisation multi-échelle pour la détermination du comportement mécanique des graves routières traitées aux liants : Application à la valorisation des Mâchefers d'Incinération de Déchêts Non Dangereux." Thesis, Rennes, INSA, 2018. http://www.theses.fr/2018ISAR0001/document.
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Dans ce travail, il est question d'étudier la faisabilité d'une valorisation en techniques routières de granulats de Mâchefers d'Incinération des Dèchets Non Dangereux (MIDND). Cette étude se base en premier lieu sur une analyse expérimentale ayant permis d'obtenir leurs propriétés élastiques. Ces propriétés servent de données d'entrée à une modélisation multi-échelle hiérarchique développée pour étudier le comportement mécanique de graves base de MIDND traitées aux liants (ciment et bitume). La campagne expérimentale originale sur des particules de mâchefers a permis de les cartographier au Microscope Electronique à Balayage (MEB Pour ces particules, des modules d'élasticité moyens réduits variant de 15 à 68 GPa ont été trouvés par le biais de tests d'indentation en appliquant méthode de «Olivier and Pharr ». Les analyses chimiques ponctuelles qualitatives (EDS) effectuées ont permis d'obtenir la composition chimique des granulats de mâchefers. Partant d'une granulométrie de particules de MIDND 0/25 qui a fait l'objet d'une étude expérimentale [BEC 07], nous avons mis en place des modèles numériques 3D de grave routière traitée aux liants dans des Volumes Elémentaires Représentatifs (VER). Ces modèles sont basés sur une stratégie de modélisation dite « multi-échelles » hiérarchique. Deux types de liant sont étudiés : le ciment CEM 1 42,5 R et le bitume de [NGU 08). Pour les deux types de liant, les agrégats traités ont été décomposés en deux VER : sub-mesoscopique (0/6) et mesoscopique (6/25). Une application à valorisation des MIDND en techniques routières est faite dans les deux cas. Avec un traitement à 3% de ciment, une campagne de simulations numériques "Laboratoire virtuel" a été menée. A l'échelle sub-mesoscopique, des simulations multiaxiales menées sur le VER, ont conduit à l'obtention des paramètres permettant d'alimenter un modèle d'endommagement plastique utilisé à l'échelle mesoscopique pour différents degrés d'hydratation. A l'échelle mesoscopique, les caractéristiques mécaniques de la grave routière traitée au ciment, habituellement déterminées par le biais d'expérimentations, ont été retrouvées. La modélisation développée a ensuite été validée e comparant nos résultats numériques et quelques résultats expérimentaux de [BEC 07]. Avec un traitement à 5% de bitume, des tests de relaxation de contraintes ont été effectués aux deux échelles ct ont permis d'obtenir les propriétés thermo-rhéologiques de la grave de mâchefers traités au bitume : les modules de relaxation sont exprimés sous la forme de séries de Prony à une température de référence de 0 °C ; par ailleurs, les constantes de la loi Williams-Landel-Ferry (WLF) pour décrire le comportement thermo- rhéologiquement simple sont identifiées. Les séries de Prony sont obtenues par l'intermédiaire des modules élastiques normalisés. Les constantes de 1 WLF obtenues sont C 1 = 20 °C-1 ct C2 = 130 °C. La validation des paramètres identifiés a été faite en comparant les réponses du matériau hétérogène de grave-bitume et celles d'un matériau homogène à qui nous avons donné les propriétés identifiées tirées du matériau hétérogèneIn this work, the feasibility of a valorisation in road engineering of non-hazardous waste incineration bottom ash aggregates (NHWI) is investigated. This study is first based on an experimental determination of the elastic properties of the bottom ash particles. These properties serve as input data for hierarchical multi-scale modelling developed to study the mechanical behaviour of aggregates treated with binders (cement and bitumen). The original experimental campaign on the bottom ash particles allowed them to be mapped to the Scanning Electron Microscope (SEM). For the particles, a mean reduced modulus of elasticity in between 15 and 68 GPa was found by means of indentation tests and applying the "Olivier and Phan method. The chemical analysis of the aggregates was obtained using qualitative point chemical analyzes (OHS). Based on a 0/25 particle size distribution of NHWI, which was the subject of an experimental study [BEC 07] , we have implemented two 30 models < road materials treated with binders in Representative Elementary Volumes (REV). These models are based on a hierarchical multi-scale modelling strategy. Two types of binder are studied: cement CEM I 42.5 R and bitumen of [NGU 08]. For both types of binder, the treated aggregates we divided into two REV, at respectively the sub-mesoscale (0/6 mm) and the mesoscale (6/25 mm). An application to the valorisation of NHWI bottom ashes in road engineering is studied in both cases. With a 3% cement treatment, a numerical simulation campaign "Virtual Laboratory" was conducted. At the sub-mesoscale, the input parameters for the Concrete Damaged Plasticity Model used at the mesoscale are determined. At the mesoscale, the mechanical characteristics of the road materials usually determined through experiments have been found. The developed simulation strategy has been validated by comparing our numerical results and son experimental results of [BEC 07]. With a 5% bitumen treatment, stress relaxation tests carried out at the two scales enable one to obtain the thermo-rheological properties of the Bitumen Bound Gravel. These properties are the Prony series at a reference temperature of 0°C and the Williams-Landei- Ferry (WLF) law constants. Prony series are obtained by means of standardized elastic moduli. The obtained WLF law constants are Cl = 20 °C-1 and C2 = 130 °C. The numeric simulations have been validated by comparing the responses of heterogeneous and corresponding homogeneous materials
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Zahid, Bilal. "Riot helmet shells with continuous reinforcement for improved protection." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/riot-helmet-shells-with-continuous-reinforcement-for-improved-protection(ef2e889d-28c0-42b7-8fd6-20b290e1563e).html.
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The present research aims to develop a novel technique for creation of composite riot helmet shells with reinforcing fibre continuity for better protection against low velocity impacts. In this research an innovative, simple and effective method of making a single-piece continuously textile reinforced helmet shell by vacuum bagging has been established and discussed. This technique also includes the development of solid collapsible moulding apparatus from non-woven fibres. Angle-interlock fabric due to its good mouldability, low shear rigidity and ease of production is used in this research. Several wrinkle-free single- piece composite helmet shells have been manufactured. Low-velocity impact test on the continuously reinforced helmet shells has been carried out. For this purpose an in-house helmet shell testing facility has been developed. Test rig has been designed in such a way that the impact test can be carried out at different locations at the riot helmet shell. Low-velocity impact test has been successfully conducted on the developed test rig. The practical experimentation and analysis revealed that the helmet shell performance against impact is dependent on the impact location. The helmet shell top surface has better impact protection as compared to helmet shell side and back location. Moreover, the helmet shell side is the most at risk location for the wearer. Finite Element models were created and simulated in Abaqus software to investigate the impact performance of single-piece helmet shells at different impact locations. Models parts have been designed in Rhinoceros software. Simulated results are validated by the experimental result which shows that the helmet top position is the safest position against an impact when it is compared to helmet back and helmet side positions.
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Haghighattalab, Armin. "Finite Element Modeling of Spiral Frequency Steerable Acoustic Transducers (FSATs) for guided waves based Structural Health Monitoring of plate-like structures." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016.
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Structural Health Monitoring (SHM) is an emerging area of research associated to improvement of maintainability and the safety of aerospace, civil and mechanical infrastructures by means of monitoring and damage detection. Guided wave structural testing method is an approach for health monitoring of plate-like structures using smart material piezoelectric transducers. Among many kinds of transducers, the ones that have beam steering feature can perform more accurate surface interrogation. A frequency steerable acoustic transducer (FSATs) is capable of beam steering by varying the input frequency and consequently can detect and localize damage in structures.
Guided wave inspection is typically performed through phased arrays which feature a large number of piezoelectric transducers, complexity and limitations. To overcome the weight penalty, the complex circuity and maintenance concern associated with wiring a large number of transducers, new FSATs are proposed that present inherent directional capabilities when generating and sensing elastic waves. The first generation of Spiral FSAT has two main limitations. First, waves are excited or sensed in one direction and in the opposite one (180 ̊ ambiguity) and second, just a relatively rude approximation of the desired directivity has been attained. Second generation of Spiral FSAT is proposed to overcome the first generation limitations.
The importance of simulation tools becomes higher when a new idea is proposed and starts to be developed. The shaped transducer concept, especially the second generation of spiral FSAT is a novel idea in guided waves based of Structural Health Monitoring systems, hence finding a simulation tool is a necessity to develop various design aspects of this innovative transducer. In this work, the numerical simulation of the 1st and 2nd generations of Spiral FSAT has been conducted to prove the directional capability of excited guided waves through a plate-like structure.
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Hoikka, Arvid. "Strength simulations of tension bars for heavy lifting." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-68771.
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Proplate, a world leading company, is expert on volume-based cutting and machining of both ordinary steel as well as stainless steel. One of Proplate’s mayor products is tension bars, which is a component made to balance high forces and give stability to structures such as cranes, buildings, bridges and much more. Proplate builds their tension bars in different high strength steel materials, purchased from SSAB, and sells them worldwide. Proplate would like to market themselves better and wishes to produce a catalogue for the maximum load that can be applied to their tension bars, as competitors Pretec and Macalloy, already have for their tension bars. The purpose of the project has been to investigate the tension bars and the maximum load they can withstand before failure. The tension bars have been modeled in the CAD-program Creo Parametric, and then sent to the finite element method program ABAQUS to analyze their structural strength. Three different types of tension bars, and a fourth tension bar (called the walnut-strap) used as a connecting element between some of the tension bars, were investigated. They were modeled with sprints, to hold several tension bars together, and with a construction called loader, to simplify the model load application step. The three different types of tension bars have been analyzed as individual and also when connected to other tension bars. Some tension bars could be directly connected to each other with sprints, and some used the walnut-strap to connect other tension bars to each other. The project was limited to fatigue analyses, which is an important factor to control. This could instead be a great continuation of the project. The results from the strength analyses show that the stress is higher at the surfaces around the hole at the end of each tension bar, and the maximum load the tension bars can withstand depends on this area. The length, thickness and orientation of the tension bar has been varied, and the maximum load that each model can withstand has been listed. The length and direction of the tension bars did not influence the result for singular tension bars, but the thickness did. Both the length and the thickness of the tension bars did influence the result when multiple tension bars where connected to each other. Tables have been derived which shows the absolute maximum load that the tension bars can withstand. Proplate can use the tables in their catalogue, and they can also put a safety factor on the models to make them safer. Another part of the study was to investigate advantages and disadvantages with if the sprints, the connecting element between the tension bars, were replaced with screws instead. The result describes the yield strength needed for the screws and how the structures would behave compared to the current structure. A larger investigation into the effect of using screws may be one way to continue the work after this project, together with other investigations of, for instance, the use of compression bars.Proplate är ett världsledande företag, som är experter på volymbaserad skärning och tillverkning i både vanligt stål såväl som rostfritt stål. En av Proplates huvudprodukter är deras dragstag, som är en komponent gjord för att balansera stora krafter och tillbringa stabilitet till strukturer, exempelvis lyftkranar, byggnader, broar med mera. Proplate bygger sina dragstag med hjälp av olika typer av höghållfasta stålsorter, köpta från SSAB, och säljer sedan produkterna över hela världen. Proplate skulle vilja marknadsföra sig bättre och önskar att ta fram en katalog över den maximala kraften som kan appliceras på dragstagen, vilket konkurrenter som Macalloy och Pretec redan har för sina dragstag. Syftet med projektet är att undersöka dragstagen och den maximala kraften som dragstagen klarar av innan de går sönder. Dragstagen har modellerats upp i CAD-programmet Creo Parametric, och sedan skickats till finita-elementmetodsprogrammet ABAQUS för hållfasthetsanalyser. Tre olika typer av dragstag, och en fjärde variant (kallad valnöts-staget) som använts som ett sammankopplande element mellan olika typer av dragstagen, har undersökts. De har modellerats tillsammans med sprintar, för att hålla samman flera dragstag, och en konstruktion vid namn loader, som ska förenkla kraftapplikationssteget i analyserna. De tre olika typerna av dragstag har analyserats individuellt och sammankopplade till andra dragstag samtidigt. Några av dragstagen kunde direkt sammankopplas till andra dragstag med hjälp av sprintar, men andra behövde valnöts-staget för att sammankoppla dragstagen till varandra. Projektet var avgränsat så att utmattningslaster, vilket är en mycket viktig faktor, inte analyserades. Resultatet från hållfasthetsanalyserna visar att spänningarna i ytan kring ett hål i kanterna av dragstagen blir som störst, och den maximala kraften som dragstagen kan klara av är beroende på denna yta. Dragstagens längd, tjocklek och orientering i rummet har varierat, och den maximala kraften som varje modell kan klara av har tabellerats. Dragstagens längd och riktning i rummet påverkade inte resultatet när individuella dragstag analyserades, men dess tjocklek gjorde det. Både längden och tjockleken av dragstagen påverkade resultatet när flera dragstag blivit sammankopplade till varandra. Tabellerna visar den absolut maximala kraften som dragstagen kan klara av. Proplate kan använda dessa tabeller till deras katalog, och de kan också lägga till en säkerhetsfaktor på modellerna för att göra dem säkrare. En annan del av analyserna var att undersöka fördelarna och nackdelarna om sprintarna, som är det sammankopplande elementet mellan de olika dragstagen, blivit utbytta mot skruvar istället. Resultatet beskriver vilken sträckgräns som skulle behövas för skruvarnas material och hur strukturen skulle bete sig i jämförelse till den nuvarande strukturen. En större undersökning angående effekten med skruvar kan vara en bra fortsättning på arbetet efter detta projekt, tillsammans med andra undersökningar som exempelvis angående användning av tryckstag.
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Profota, Martin. "Pevnostní návrh ostruhy letadla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318638.
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This master thesis deals with computational stress-strain analysis of the tailskid of airplane L410 NG with main focus firstly the check current design of the tailskid and then the design another design solution with the able to absorb as much as possible the deformation energy. Solution of this problem is performed using computational modeling utilizing numerical simulation of quasi-static and crash deformation load of the tailskid with using explicit Finite Element Method (FEM) in program ABAQUS v6.14. After the introduction with problem situation and tailskid assembly introductory part is devoted to the research study of various designs of the tailskid for different types of airplanes. There follows these theoretical general principles of thin-walled structures and buckling of them. Before the creating of the computational model itself, the explicit form of the Finite Element Method is better described. The conclusion of this thesis deals with the mutual comparison of the most advantageous design variants of the tailskid and the selection of the most suitable one of them for the airplane L410 NG.
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Vakada, Krishna Chaitanya. "USE OF ADVANCED MATERIAL MODELING TECHNIQUES IN LARGE-SCALE SIMULATIONS FOR HIGHLY DEFORMABLE STRUCTURES." University of Akron / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=akron1132331555.
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Courard, Amaury. "PGD-Abaques virtuels pour l'optimisation géométrique des structures." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLN010/document.
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Lors de l'optimisation géométrique de structures, un grand nombre d'évaluations de champs est nécessaire. L'idée, développée dans cette thèse, est la construction efficace et rapide d'approximations de ces champs à travers la Proper Generalized Decomposition (PGD), une méthode de réduction de modèle. Les résultats, calculés une fois pour toutes, sont stockés dans des abaques virtuels pour une utilisation ultérieure dans un processus d'optimisation. Le problème considéré est paramétrique et les paramètres définissent la géométrie. Ce type de problème est particulièrement adapté à la PGD. En effet, de nombreux travaux ont traité de la résolution de problèmes paramétriques et des premières études ont porté, en particulier, sur la prise en compte de paramètres géométriques. Toutefois, ce qui caractérise nos travaux est d'aller vers des outils aptes à traiter des situations significatives de la complexité des problèmes rencontrés au niveau industriel. En particulier, l'exploitation de codes éléments finis commerciaux est une contrainte majeure. Il a été décidé de développer des méthodes permettant de traiter des problèmes à paramètres géométriques par la PGD, et, en partenariat avec AIRBUS Defence & Space, d'appliquer ces techniques à un démonstrateur industriel présentant une géométrie complexe (type splines) et de fortes non-linéarités (géométriques, matériaux). Notre démarche a été implémentée dans un process industriel utilisant des codes éléments finis commerciaux. On propose aussi une nouvelle extension de la PGD aux paramètres discrets autorisant la prise en considération, dans une même résolution, de configurations de structures complètement différentes (cas de chargement, matériaux, etc.)During shape optimisation of structures, numerous evaluations of fiels are necessary. The idea, developed in this PhD thesis, is the efficient construction of approximations of these fiels through the Proper Generalized Decomposition (PGD), a model reduction technique. The results, computed once and for all, are stored in virtual charts for a subsequent use into an optimisation process. Geometry variations correspond to a parametric problem, where the parameters is the geometry. This kind of problem is well suited for PGD. Many studies dealt with the resolution of parametric problems and recent works treated, particularly, the introduction of geometric parameters. However, our approach is to deal with configurations of the complexity of industrial problems. The use of commercial finite elements software is a crucial issue. It was decided, in partnership with AIRBUS Defence & Space, to develop techniques allowing the resolution of geometrically parametrised problems thanks to PGD and to apply them to an industrial demonstrator. The geometry considered is defined by splines and the behaviour of the structure is highly non-linear (geometric and material non-linearities). The approach was implemented into a genuine industrial design process using commercial finite elements software. The thesis proposed, also, a new extension of PGD to discrete parameters. It allows to take into account completely different configurations (loadings, materials, etc.) in the same resolution
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Lima, Verônica Aparecida Lopes. "Desenvolvimento de uma arquitetura reconfigurável para o processamento de modelos no ambiente ABACUS /." Ilha Solteira : [s.n.], 2007. http://hdl.handle.net/11449/87216.
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Orientador: Norian MarranghelloBanca: Nobuo Oki
Banca: Wang Jiang Chau
Resumo: O objetivo deste trabalho é o desenvolvimento de uma arquitetura reconfigurável estaticamente, de um elemento de processamento (MPH) para o ambiente de simulação de circuitos ABACUS. Este elemento de processamento consiste de um conjunto de unidades funcionais que podem ser relacionadas por meio de algumas palavras de controle armazenadas na ROM, e cuja interconexão pode ser alterada para que o hardware de processamento se adapte ao modelo do elemento de circuito a ser simulado. O projeto foi descrito em linguagem VHDL e simulado com o auxílio do software QUARTUS II.
Abstract: The aim of this work is the development of a statically reconfigurable architecture, of a processing element (MPH) for the ABACUS circuit simulation environment. This processing element consists of a set of functional units that can be related by means of some control words stored in the ROM, and whose interconnection can be modified so that the processing hardware be adapted to the model of the circuit element to be simulated. The project was described in VHDL, and simulated with the aid of Quartus II software.
Mestre
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Ng, Priscilla, Priscilla Ng, and Priscilla Ng. "Simulating Particle Packing During Powder Spreading For Selective Laser Melted Additive Manufacturing Using The Discrete Element Method In Abaqus." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2162.
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Metal additive manufacturing allows for the rapid production of complex parts that are otherwise impractical using conventional subtractive manufacturing techniques. Applications for additive manufacturing span across a broad array of industries including aerospace, automotive, and medical, among many others. One metric of printing success is material properties, including part density. While there has been extensive research completed for the density of printed parts, there is little published work concerning powder packing density on the build plate associated with powder spreading.
In this thesis, a Discrete Element Method (DEM) model was created in Abaqus to simulate the spreading behavior of particles through a single sweep of a spreader blade . Spreading behavior was investigated for three different build plate configurations: a flat build plate, a build plate with a small protruding feature, and a build plate with the same protruding feature split into quarters. For each configuration, the 2D packing behavior of the particles were analyzed during the powder spreading process. Different packing patterns seen in the 2D packing behavior were further analyzed to determine particle packing density, analogous to unit cell packing, and to predict 3D packing behavior and packing density. Additionally, particle packing density was measured following simulation using 2D image analysis to quantify powder spreading around, and interaction with, previously fused structures on the build plate. We found that the local packing fraction is measurably disrupted when particles interact with build plate features, providing insights into part density and short loading during part fabrication.
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Lima, Verônica Aparecida Lopes [UNESP]. "Desenvolvimento de uma arquitetura reconfigurável para o processamento de modelos no ambiente ABACUS." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/87216.
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O objetivo deste trabalho é o desenvolvimento de uma arquitetura reconfigurável estaticamente, de um elemento de processamento (MPH) para o ambiente de simulação de circuitos ABACUS. Este elemento de processamento consiste de um conjunto de unidades funcionais que podem ser relacionadas por meio de algumas palavras de controle armazenadas na ROM, e cuja interconexão pode ser alterada para que o hardware de processamento se adapte ao modelo do elemento de circuito a ser simulado. O projeto foi descrito em linguagem VHDL e simulado com o auxílio do software QUARTUS II.
The aim of this work is the development of a statically reconfigurable architecture, of a processing element (MPH) for the ABACUS circuit simulation environment. This processing element consists of a set of functional units that can be related by means of some control words stored in the ROM, and whose interconnection can be modified so that the processing hardware be adapted to the model of the circuit element to be simulated. The project was described in VHDL, and simulated with the aid of Quartus II software.
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Andreasson, Eskil. "Realistic Package Opening Simulations : An Experimental Mechanics and Physics Based Approach." Licentiate thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00610.
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A finite element modeling strategy targeting package opening simulations is the final goal with this work. The developed simulation model will be used to proactively predict the opening compatibility early in the development process of a new opening device and/or a new packaging material. To be able to create such a model, the focus is to develop a combined and integrated physical/virtual test procedure for mechanical characterization and calibration of thin packaging materials. Furthermore, the governing mechanical properties of the materials involved in the opening performance needs to be identified and quantified with experiments. Different experimental techniques complemented with video recording equipment were refined and utilized during the course of work. An automatic or semi-automatic material model parameter identification process involving video capturing of the deformation process and inverse modeling is proposed for the different packaging material layers. Both an accurate continuum model and a damage material model, used in the simulation model, were translated and extracted from the experimental test results. The results presented show that it is possible to select constitutive material models in conjunction with continuum material damage models, adequately predicting the mechanical behavior of intended failure in thin laminated packaging materials. A thorough material mechanics understanding of individual material layers evolution of microstructure and the micro mechanisms involved in the deformation process is essential for appropriate selection of numerical material models. Finally, with a slight modification of already available techniques and functionalities in the commercial finite element software AbaqusTM it was possible to build the suitable simulation model. To build a realistic simulation model an accurate description of the geometrical features is important. Therefore, advancements within the experimental visualization techniques utilizing a combination of video recording, photoelasticity and Scanning Electron Microscopy (SEM) of the micro structure have enabled extraction of geometries and additional information from ordinary standard experimental tests. Finally, a comparison of the experimental opening and the virtual opening, showed a good correlation with the developed finite element modeling technique. The advantage with the developed modeling approach is that it is possible to modify the material composition of the laminate. Individual material layers can be altered and the mechanical properties, thickness or geometrical shape can be changed. Furthermore, the model is flexible and a new opening device i.e. geometry and load case can easily be adopted in the simulation model. Therefore, this type of simulation model is a useful tool and can be used for decision support early in the concept selection of development projects.
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Aimene, Yamina Boisse Philippe. "Approche hyperélastique pour la simulation des renforts fibreux en grandes transformations." Villeurbanne : Doc'INSA, 2008. http://docinsa.insa-lyon.fr/these/pont.php?id=aimene.
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Aimene, Yamina. "Approche hyperélastique pour la simulation des renforts fibreux en grandes transformations." Lyon, INSA, 2007. http://theses.insa-lyon.fr/publication/2007ISAL0083/these.pdf.
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Un modèle de comportement hyperélastique est proposé pour la simulation des renforts fibreux de composites en particulier tissés. Son objectif est de simuler à l’échelle macroscopique des opérations de mise en forme. Il représente une alternative aux approches continues hypoélastiques existantes. Un potentiel énergétique simple reproduisant les non linéarités matérielles connues des renforts tissés est proposé. Classiquement, les modes de déformations se caractérisent par des déformations faibles dans la direction des mèches et de grandes déformations de cisaillement plan. Le modèle est implémenté dans une routine utilisateur Vumat d’Abaqus/Explicit. La sensibilité de la solution à la densité de maillage et la pertinence des résultats ont été analysées pour différents tests de référence en grandes transformations : cisaillement pur et simple, cisaillement pur - extension. Enfin, le modèle est testé pour simuler une opération de formage par poinçon hémisphérique. Des résultats satisfaisants sont obtenus, notamment sur la prise en compte ou non de la rigidité associée au cisaillement plan entre les mèchesA hyperelastic model is proposed to simulate the fibre composites. Its objective is to simulate at the macroscopic level the forming operation. It represents an alternative to hypo-elastics continuous approaches. A simple energetic potential reproducing the non linearities known of woven is proposed. Classically, deformation modes are characterized by weak strains in the fibre direction and large plane shear strains. The model is implemented in routine user of Vumat of Abaqus/Explicit. The sensitivity of the solution to the number of elements and the relevancy of the results are analysed for different reference tests of large strain: picture frame test, simple shear test and simple shear -extension test. Finally, the model is tested to simulate the forming with hemispherical punch. Satisfactory results were obtained especially when taking or not in account the shear rigidity in the simulation
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Ščerba, Bořek. "Vliv nastavení a konfigurace rovnačky na výsledky simulace kosoúhlého rovnání." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-418209.
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Analytical methods or implicit finite element method (FEM) with beam elements to model straightened bar were used to analyze straightening process in multi-staggered cross-roll straighteners up to now. These are effective but require certain simplifications. Aim of this thesis is to create an explicit FEM model allowing usage of solid elements for circular bar without disproportional increase of computational time. This may lead to deeper understanding of the straightening process. The model is to be verified using straightening tables and then used to quantify influence of rollers configuration on results of the straightening process.
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Alves, José Augusto Camargo. "Estudo da conformabilidade de abas convexas da liga de alumínio AA2024-O no processo de hidroconformação de chapas." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264433.
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Orientador: Sérgio Tonini ButtonDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: O processo sheet hydroform, ou hidroconformação de chapas, é realizado por meio de uma prensa composta por uma membrana de borracha, preenchido com um fluido hidráulico cuja função é atuar como uma matriz, exercendo esforços sobre uma chapa de metal (blank), que é então empurrada contra um punção rígido, fazendo-o adquirir o formato deste. Embora este processo seja amplamente utilizado para a produção de pequenos lotes de peças metálicas de formato complexo e de espessura reduzida, ele exige habilidades de quem o define, pois se por um lado pode ser visto como simples por empregar apenas um molde maciço, por outro, a ausência de um sistema macho-fêmea capaz de garantir um completo travamento do blank pode ser encarado como um problema por permitir movimentos indesejados do material, que muitas vezes resultam na formação de rugas ou outros defeitos. Baseando-se nesses conceitos, o propósito deste trabalho foi o de mapear, por meio de simulações e ensaios práticos, a conformabilidade de abas convexas da liga de alumínio AA2024-0 de quatro espessuras quando submetidas a diferentes combinações de raio de curvatura e comprimento de aba. Deste modo, foi possível definir quais combinações destes parâmetros possibilitam a obtenção de componentes conformados adequadamente, isentos de rugas e outros defeitos macroscópicos, e ainda, quais condições levam à formação de irregularidades na aba conformada acima do limite preestabelecido, exigindo o emprego de prensa-chapas especiais, também conhecidos como dams, capazes de evitar a ocorrência de tais desvios. Com base nos resultados obtidos pode-se constatar que a ocorrência de rugas está associada principalmente à altura da aba conformada e não se altera significativamente quando a espessura do blank é modificada. Além disso, foi possível notar que raios de curvaturas maiores proporcionam menores valores de deformação compressiva na região conformada, permitindo obter abas mais altas e sem rugas
Abstract: Hydroform, or sheet metal fluid forming, is performed using a fluid cell press, in which the hydraulic fluid acts on the metallic blank pushing it against the male tool, acquiring its geometry. It is widely employed to manufacture small batches of complex and low thick components. If by one point of view it can be seen as simple, involving just a single rigid block as tool, by the other hand the absence of a rigid punch in certain cases can be a limitation, since it may allow the blank to move incorrectly during the process, causing wrinkles or other macro defects. Based on this limitation, the aim of this study was to define, using computational simulations and practical tests, the shrink flange formability limit of four different thickness aluminum alloy sheets when submitted to different combinations of curvature radius and flange length. As result, it could be seen which combinations can lead the material to be formed properly and which may cause failures, requiring special blank holders, known as dams, to avoid this problems. Based on the results, it can be verified that wrinkles nucleation is mainly associated with flange height and it does not change significantly when using blanks with different thicknesses. Furthermore, it could be noted that bigger curvature radius implies in smaller compressive strain on formed region, allowing to obtain higher flanges without wrinkles in these conditions
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
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Canales, Aguilera Diego. "Stratégies numériques avancées pour la simulation efficace de procédés de soudage conventionnels et non conventionnels : Une approche de réduction de modèles." Thesis, Ecole centrale de Nantes, 2017. http://www.theses.fr/2017ECDN0012/document.
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Les simulations numériques représentent un outil fondamental pour la conception et l'optimisation de procédés industriels de fabrication tels que le soudage. Malgré le développement impressionnant des méthodes numériques et des moyens de calcul utilisables, la complexité des procédés de fabrication et les nouvelles exigences des industries les plus avancées obligent à repenser les méthodes, les stratégies et les algorithmes de simulation disponibles. Dans cette thèse, de nouvelles méthodes numériques avec une approche de Réduction des Modèles sont proposées, une discipline consolidée qui a fourni des solutions étonnantes dans différentes applications, comme les procédés de fabrication avancés. Tout d'abord, différentes stratégies sont proposées pour la simulation efficace des procédés de soudage conventionnel, à cet effet, l'utilisation de Computational Vademecums est introduite. L’introduction de ces abaques numériques améliorent des méthodes telles que : les Éléments Finis Généralisés pour le calcul thermique, l'approche local-global pour le calcul mécanique et enfin, la construction directe des abaques numériques utiles pour la phase de pré-design. En second lieu, un solveur PGD efficace est présenté pour les simulations thermo-mécaniques de soudage par friction-malaxage. Cette thèse montre comment la réduction des modèles,en plus d'être une fin en soi, peut être un excellent ingrédient pour améliorer l'efficacité des méthodes numériques traditionnelles. Cela représente un grand intérêt pour l'industrieNumerical simulations represent a fundamental tool for the design and optimization of industrial manufacturing processes such as welding. Despite the impressive development of the numerical methods and the means of calculation, the complexity of these processes and the new demands of the more advanced industries make it necessary to rethink the available methods, strategies and simulation algorithms. In this thesis, we propose new numerical methods with a Model Order Reduction approach, a consolidated discipline that has provided surprising solutions indifferent applications, such as advanced manufacturing processes. First, different strategies for the efficient simulation of conventional welding processes are proposed. To this end, the use of Computational Vademecums is introduced for the improvement of methods such as the Generalized Finite Element for thermal calculation, the local-global approach for the mechanical calculation or the direct construction of vademecums useful for predesign phases. Then, an efficient PGD solver for thermomechanical simulations for friction stir welding is presented. This thesis shows how Model Reduction, besides being an end, it can be an excellent ingredient to improve the efficiency of traditional numerical methods, with great interest for the industry
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Sarti, Matteo. "Preliminary study for the assessment of discontinuity’s size through Machine Learning algorithms." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/22874/.
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During the last two decades there has been a huge breakthrough in the Structural Health Monitoring field, especially in the study of Acoustic Emissions (AE), to get qualitative and quantitative damage-related information.
This thesis attempts to focus on the possibility of obtaining an automatic estimate of small discontinuity’s length in an aluminium plate, by analysing some impinging signals when they interfere with the defect itself. The novel aspect about this analysis is that it was conducted through “trained” classification and regression algorithms that have been able, up to some extent, to automatically classify and predict the desired responses. This means that Artificial Intelligence, in particular Machine Learning techniques, were employed and played an important role within either the identification and the predictive part of this study.
Due to the SARS-CoV-2 global pandemic, and the consequent closure of the US embassies, it was not possible to obtain the Visa and go to Clarkson University to perform the experimental campaign there. Therefore, in order to collect the raw signals for the subsequent analysis, a comparison between Abaqus CAE and OnScale software was firstly enforced, and eventually the latter was chosen to perform the whole set of numerical simulations exploiting a pitch-catch configuration.
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Albahttiti, Mohammed T. "Wheat fiber from a residue to a reinforcing material." Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/13725.
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Master of ScienceDepartment of Civil Engineering
Hayder A. Rasheed
Throughout history natural fiber was used as one of the main building materials all over the world. Because the use of such materials has decreased in the last century, not much research has been conducted to investigate their performance as a reinforcing material in cement and concrete. In order to investigate one of the most common natural fibers, wheat fibers, as a reinforcing material, 156 mortar specimens and 99 concrete specimens were tested. The specimens were tested in either uniaxial compression or flexure. The uniaxial compression test included 2 in (50.8 mm) mortar cubes and 4x8 in (101.6 x 203.2 mm) concrete cylinders. As for the flexure test, they were either 40x40x160 mm cementitious matrix prisms or 6x6x21 in (152.4x152.4x533.4 mm) concrete prisms. Several wheat fibers percentages were studied and compared with polypropylene fiber as a benchmarking alternative. The average increase in the uniaxial compression strength for cementitious matrix cubes reinforced with 0.5% long wheat fiber exceeded that of their counterparts reinforced with polypropylene fiber by 15%. Whereas for concrete cylinders reinforced with 0.75% long wheat fiber, their strength exceeded that of their counterparts reinforced with polypropylene fiber by 5% and that of the control by 7%. The flexural strength of cementitious matrix prisms reinforced with 0.75% long wheat fiber exceeded that of their counterparts reinforced with polypropylene fiber by 27%. Meanwhile, concrete prisms reinforced with both long wheat fiber and polypropylene fiber showed deterioration in strength of up to 17%. Finally, ABAQUS models were developed for concrete cylinders and prisms to simulate the effect of inclusion of the wheat fibers.
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Wang, Hong-Yi, and 王弘毅. "Seismic Simulation of the PV Frame Joint Based on ABAQUS." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/60435563363352810322.
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碩士國立臺灣大學
土木工程學研究所
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The research is based on the shaking-table tests of the shed-frame type photovoltaic (PV) system in National Center for Research on Earthquake Engineering (NCREE). We observe the dynamic behavior and the failure process of the aluminum shed-frame structure under the earthquake in the tests. During the tests, the shed-frame structure does not collapse and has no obvious structural damage. The tests verify the results of the modal analysis by SAP2000 in this research, giving designers a good foundation on the aseismic design of such structure. However, a small gap is discovered at the middle column joint after the tests. Moreover, the data collected in the test show that the natural frequency of structure decreases in the tests. This phenomenon indicates the joint of structure yields after the tests. Considering the simulation model of the joints are simplified in SAP2000, the research uses ABAQUS to analyze the detailed joint behavior of the shed-frame structure in this tests. Combined with experiment data and simulation by SAP2000, the simulation by ABAQUS verifies the failure process of the shed-frame structure in the tests and estimates the decreased frequency of the shed-frame structure under joint yielding status. The simulation result based on ABAQUS shows that the failure process of the joint is close to what was observed in the shaking-table tests. The research approach to simulate the failure process of the joints by ABAQUS is effective in the seismic simulation. Based on the simulation results, the research makes some suggestions to improve reliability and safety of the shed-frame type PV system.