Dissertations / Theses: 'Finite element analysis of composites using Abaqus'

1

Pederson, Joy. "Finite element analysis of carbon fiber composite ripping using ABAQUS." Connect to this title online, 2009. http://etd.lib.clemson.edu/documents/1239896203/.

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Joshi, Ninad Milind. "Study of the Effect of Unidirectional Carbon Fiber in Hybrid Glass Fiber / Carbon Fiber Sandwich Box Beams." University of Dayton / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1386188162.

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Miltenberger, Louis C. "Finite element modeling of the filament winding process using ABAQUS." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-06232009-063022/.

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Feng, Fan. "Flutter Analysis of Stonecutters Cable-stayed Bridge using Finite Element Model." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32470.

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The current research analyzed the flutter response of the Stonecutters Cable-Stayed Bridge in Hong Kong, which has a twin deck configuration, under the effect of wind. The aerodynamic instability response of the bridge steel deck of the main span is mainly the focus of the current project. Initially, a complete finite element bridge model was created in ABAQUS finite element software, representing all the structural elements of the Stonecutters Cable-Stayed Bridge in a lumped mass bridge model. The natural frequencies and the vibration modes were validated against the data available in the literature at first. Secondly, the effect of the mean wind loading for wind speeds between 35 m/s and 211 m/s were determined. The vertical and horizontal displacements and the torsional angle at mid-span are indicated to determine the bridge performance under mean wind load. Moreover the flutter instability was modeled based on Scanlan’s theory and the response of the bridge model at several different locations along the main and the side span and the top of the tower, were determined for wind speeds of 35 m/s and higher, where this critical aerodynamic instability is expected to occur. In addition, the responses of the bridge under natural wind data were also determined by applying a wind speed recorded data to the bridge model. Finally, the critical flutter wind speed and the flutter frequency were determined by Fast Fourier Transform in MATLAB program. The flutter onset wind speed was also determined.

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Kim, Dooheon. "Multi-scale analysis of refractory fabric composites using finite element analysis /." Available to subscribers only, 2006. http://proquest.umi.com/pqdweb?did=1240703201&sid=6&Fmt=2&clientId=1509&RQT=309&VName=PQD.

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Thesis (M.S.)--Southern Illinois University Carbondale, 2006.
"Department of Mechanical Engineering and Energy Processes." Includes bibliographical references (leaves 59-63). Also available online.

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Roy, Sujata Thiagarajan Ganesh. "Nonlinear finite element analysis of reinforced concrete bridge deck/bridge approach slab using ABAQUS." Diss., UMK access, 2005.

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Thesis (M.S.)--School of Computing and Engineering. University of Missouri--Kansas City, 2005.
"A thesis in civil engineering." Typescript. Advisor: Ganesh Thiagarajan. Vita. Title from "catalog record" of the print edition Description based on contents viewed June 26, 2006. Includes bibliographical references (leaves 91-93). Online version of the print edition.

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Degl'Incerti, Tocci Corrado. "Analysis of Composites using Peridynamics." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/25351.

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Since the last century a lot of effort has been spent trying to analyze damage and crack evolution in solids. This field is of interest because of the many applications that require the study of the behavior of materials at the micro- or nanoscale, i.e. modeling of composites and advanced aerospace applications. Peridynamics is a recently developed theory that substitutes the differential equations that constitute classical continuum mechanics with integral equations. Since integral equations are valid at discontinuities and cracks, peridynamics is able to model fracture and damage in a more natural way, without having to work around mathematical singularities present in the classical continuum mechanics theory. The objective of the present work is to show how peridynamics can be implemented in finite element analysis (FEA) using a mesh of one-dimensional truss elements instead of 2-D surface elements. The truss elements can be taken as a representation of the bonds between molecules or particles in the body and their strength is found according to the physical properties of the material. The possibility implementing peridynamics in a finite element framework, the most used method for structural analysis, is critical for expanding the range of problems that can be analyzed, simplifying the verification of the code and for making fracture analysis computationally cheaper. The creation of an in-house code allows for easier modifications, customization and enrichment if more complex cases (such as multiscale modeling of composites or piezoresistive materials) are to be analyzed. The problems discussed in the present thesis involve plates with holes and inclusions subjected to tension. Displacement boundary conditions are applied in all cases. The results show good agreement with theory as well as with empirical observation. Stress concentrations reflect the behavior of materials in real life, cracks spontaneously initiate and debonding naturally happens at the right locations. Several examples clearly show this behavior and prove that peridynamics is a promising tool for stress and fracture analysis.
Master of Science

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Berner, Joseph Michael. "Finite element analysis of damage in fibrous composites using a micromechanical model." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA277226.

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Thesis (M.S. in Mechanical Engineering and Mechanical Engineer) Naval Postgraduate School, December 1993.
Thesis advisor(s): Young W. Kwon. "December 1993." Includes bibliographical references. Also available online.

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Milliren, Eric Carlton. "Nanocomposites a study of theoretical micromechanical behavior using finite element analysis /." Thesis, Montana State University, 2009. http://etd.lib.montana.edu/etd/2009/milliren/MillirenE0509.pdf.

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Current research in nanotechnology has produced an increasing number of possibilities for advanced materials. Among those materials with potential advanced mechanical properties are fiber-reinforced composite laminates that utilize nanoscale fiber diameters. Through a combination of studying classic micromechanical models and modern computer-aided finite element analysis (FEA), the advantages for utilizing these nanofibers in advanced structural applications, such as space mirror backings, was investigated. The approach for modeling these composite structures was that of a Representative Volume Element (RVE). Using the program ABAQUS/CAE, a RVE was created with the goals of accurately comparing to the shear lag theory, effectively incorporating "interphase" zones that bond the constituents, and demonstrating effects of down-scaling fiber diameter. In this thesis, the progression of the ABAQUS model is thoroughly covered as it developed into a verified model correlating with the shear lag theory. The model produced was capable of utilizing interphase if desired, and was capable of off-axis loading scenarios. A MathCAD program was written in order to employ the published theoretical techniques, which were then compared to the FEA results for verification. The FEA model was found to work well in conjunction with the theory explored using MathCAD, after which the nanofiber FEA model showed some clear advantages over a conventional-sized model, specifically an increase in strength of the composite RVE. Finally, it was determined that the interfacial bonding strength plays a large role in the structure of the interphase zone, and thus the overall strength of the composite.

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Alsuleimanagha, Zaid, and Jing Liang. "Dynamic analysis of the Baozhusi dam using FEM." Thesis, KTH, Mark- och vattenteknik (flyttat 20130630), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171817.

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High magnitude earthquakes have devastating effects that leads to severe human and material losses; when affecting concrete gravity dams, seisms devastate the surrounding habitat through sudden release of reservoir. Dam safety is therefore a significant issue to be accounted in order to prevent the failure of dams located in seismic regions. The Baozhusi dam, the case study of this thesis, was exposed to 8.0 Ms (at the Mercalli scale) Wenchuan earthquake 2008 with intensity of (0.148 g) at the dam site. The earthquake intensity exceeded the design level of the dam (0.1 g); yet, the Baozhusi dam was not severely damaged as showed by tests. The present study case is a modeling and analyzing of the dynamical behavior of the Baozhusi dam during the earthquake duration. The results show that the horizontal component of the ground motion predominate the dynamic response of the dam. It is confirmed that the horizontal component of the ground motion crossed the dam at its axis and therefore minimizing the damages on the concrete gravity dam.

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Hammerand, Daniel C. "Geometrically-Linear and Nonlinear Analysis of Linear Viscoelastic Composites Using the Finite Element Method." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/28893.

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Over the past several decades, the use of composite materials has grown considerably. Typically, fiber-reinforced polymer-matrix composites are modeled as being linear elastic. However, it is well-known that polymers are viscoelastic in nature. Furthermore, the analysis of complex structures requires a numerical approach such as the finite element method. In the present work, a triangular flat shell element for linear elastic composites is extended to model linear viscoelastic composites. Although polymers are usually modeled as being incompressible, here they are modeled as compressible. Furthermore, the macroscopic constitutive properties for fiber-reinforced composites are assumed to be known and are not determined using the matrix and fiber properties along with the fiber volume fraction. Hygrothermo-rheologically simple materials are considered for which a change in the hygrothermal environment results in a horizontal shifting of the relaxation moduli curves on a log time scale, in addition to the usual hygrothermal loads. Both the temperature and moisture are taken to be prescribed. Hence, the heat energy generated by the viscoelastic deformations is not considered. When the deformations and rotations are small under an applied load history, the usual engineering stress and strain measures can be used and the time history of a viscoelastic deformation process is determined using the original geometry of the structure. If, however, sufficiently large loads are applied, the deflections and rotations will be large leading to changes in the structural stiffness characteristics and possibly the internal loads carried throughout the structure. Hence, in such a case, nonlinear effects must be taken into account and the appropriate stress and strain measures must be used. Although a geometrically-nonlinear finite element code could always be used to compute geometrically-linear deformation processes, it is inefficient to use such a code for small deformations, due to the continual generation of the assembled internal load vector, tangent stiffness matrix, and deformation-dependent external load vectors. Rather, for small deformations, the appropriate deformation-independent stiffness matrices and load vectors to be used for all times can be determined once at the start of the analysis. Of course, the time-dependent viscoelastic effects need to be correctly taken into account in both types of analyses. The present work details both geometrically-linear and nonlinear triangular flat shell formulations for linear viscoelastic composites. The accuracy and capability of the formulations are shown through a range of numerical examples involving beams, rings, plates, and shells.
Ph. D.

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Amin, Handren. "A comparative study of 2 CAD-integrated FE-programs using the linear static analysis." Thesis, Halmstad University, School of Business and Engineering (SET), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-2355.

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This Master’s thesis is summery of a comparative study of 2 commercial CAD-integrated

FE-programs. These FE-programs were CATIA v5 and ABAQUS 6.3-7. The primary

objective of this study is to investigate the basic FEA capabilities of CATIA and

ABAQUS 6.7-3 in performing the linear static analysis and to identify whether there are

any differences and similarities between results the both Finite Element FE codes give.

The overall research question in the present thesis is: Do different FE programs, here

CATIA and ABAQUS, give the same results for FE analysis giving the same models if

subjected to the same boundary conditions? This research seeks to achieve its aims

through making a comparative qualitative study. Certain pre-selections were performed in

advance of conducting Finite element analysis and the comparison process to ensure that

results would reflect only the most relevant and meaningful differences and similarities

between the both FE-codes. Five different 3D solid models have been selected to perform

linear static Finite element analysis on. All these models (case studies) are created in

CATIA V5 and the linear static analysis conducted on using FE-codes CATIA v5 and

ABAQUS 6.7-3. Three static responses (results) of the linear static analysis have been

adopted as criteria for comparisons purposes. These criteria were: (1) displacements, (2)

Von Mises stress, and (3) principal stress. The results of comparisons showed that there is

a very good agreement in most cases and small gap between in a few cases. Results of

this study demonstrate that the both FE-programs CATIA v5 and ABAQUS 6.7-3 have

good capabilities to perform FE-analysis and they give very near results. Reason behind

differences is that each of them uses a different algorithm for solving problems. The final

answer for the research question is given with valuable recommendations for future work

in the scope of this research.

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13

Caselman, Elijah. "Elastic property prediction of short fiber composites using a uniform mesh finite element method." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5036.

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Thesis (M.S.)--University of Missouri-Columbia, 2007.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 19, 2008) Includes bibliographical references.

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Asdal, Bent. "Static and free vibration analysis of advanced composites using shear-deformable rectangular plate finite elements." Thesis, Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/80092.

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A comparison of rectangular finite elements based on a first order shear deformation plate theory and a refined higher order plate theory is presented. Special attention is given to the representation of transverse shear strain, the phenomenon of "shear locking", and the selection of the interpolating polynomial. Both C⁰ and C¹ continuity elements are represented; the elements range from: 3 or 5 DOF per node, and 12 - 27 DOF per element. Static and free vibration analysis of isotropic and laminated plates with thicknesses ranging from extremely thin to very thick are presented, along with a convergence study. The finite element results are compared with the exact plate theory solutions. Of the elements investigated, the modified refined higher order theory element exhibits the best overall behavior.
Master of Science

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Gozluklu, Burak. "Delamination Analysis By Using Cohesive Interface Elements In Laminated Composites." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611005/index.pdf.

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Finite element analysis using Cohesive Zone Method (CZM) is a commonly used method to investigate delamination in laminated composites. In this study, two plane strain, zero-thickness six-node quadratic (6-NQ) and four-node linear (4-NL) interface elements are developed to implement CZM. Two main approaches for CZM formulation are categorized as Unified Mode Approach (UMA) and Separated Mode Approach (SMA), and implemented into 6-NQ interface elements to model a double cantilever beam (DCB) test of a unidirectional laminated composite. The results of the approaches are nearly identical. However, it is theoretically shown that SMA spawns non-symmetric tangent stiffness matrices, which may lower convergence and/or overall performance, for mixed-mode loading cases. Next, a UMA constitutive relationship is rederived. The artificial modifications for improving convergence rates such as lowering penalty stiffness, weakening interfacial strength and using 6-NQ instead of 4-NL interface elements are investigated by using the derived UMA and the DCB test model. The modifications in interfacial strength and penalty stiffness indicate that the convergence may be improved by lowering either parameter. However, over-softening is found to occur if lowering is performed excessively. The morphological differences between the meshes of the models using 6-NQ and 4-NL interface elements are shown. As a consequence, it is highlighted that the impact to convergence performance and overall performance might be in opposite. Additionally, benefits of selecting CZM over other methods are discussed, in particular by theoretical comparisons with the popular Virtual Crack Closure Technique. Finally, the numerical solution scheme and the Arc-Length Method are discussed.

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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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Saeidi, Farid. "Hygrothermal Fracture Analysis Of Fibrous Composites With Variable Fiber Spacing Using Jk-integral." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615370/index.pdf.

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In this study, a Jk-integral based computational method will be developed to conduct fracture analysis of fibrous composite laminates that possess variable fiber spacing. This study will be carried out for the fibrous composites exposed to not only thermal but also hygroscopic boundary condition, which results hygrothermal load. Formulation of the Jk-integral will be carried out by using the constitutive relations of plane orthotropic hygrothermoelasticity. One of the most important challenges of this study is to change Jk-integral formulation into domain independent form, because dealing with infinitely small domains in solving the integral would be frustrating. Developed form of Jk-integral will be merged to ANSYS, a finite element analysis software. Numerical results will be generated so as to assess the influence of variable fiber spacing on the modes I and II stress intensity factors, energy release rate, and the T-stress. For validation and comparison, some of the results are also obtained using Displacement Correlation Technique (DCT).

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Evans, Llion Marc. "Thermal finite element analysis of ceramic/metal joining for fusion using X-ray tomography data." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/thermal-finite-element-analysis-of-ceramicmetal-joining-for-fusion-using-xray-tomography-data(5f06bb67-1c6c-4723-ae14-f03b84628610).html.

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A key challenge facing the nuclear fusion community is how to design a reactor that will operate in environmental conditions not easily reproducible in the laboratory for materials testing. Finite element analysis (FEA), commonly used to predict components’ performance, typically uses idealised geometries. An emerging technique shown to have improved accuracy is image based finite element modelling (IBFEM). This involves converting a three dimensional image (such as from X ray tomography) into an FEA mesh. A main advantage of IBFEM is that models include micro structural and non idealised manufacturing features. The aim of this work was to investigate the thermal performance of a CFC Cu divertor monoblock, a carbon fibre composite (CFC) tile joined through its centre to a CuCrZr pipe with a Cu interlayer. As a plasma facing component located where thermal flux in the reactor is at its highest, one of its primary functions is to extract heat by active cooling. Therefore, characterisation of its thermal performance is vital. Investigation of the thermal performance of CFC Cu joining methods by laser flash analysis and X ray tomography showed a strong correlation between micro structures at the material interface and a reduction in thermal conductivity. Therefore, this problem leant itself well to be investigated further by IBFEM. However, because these high resolution models require such large numbers of elements, commercial FEA software could not be used. This served as motivation to develop parallel software capable of performing the necessary transient thermal simulations. The resultant code was shown to scale well with increasing problem sizes and a simulation with 137 million elements was successfully completed using 4096 cores. In comparison with a low resolution IBFEM and traditional FEA simulations it was demonstrated to provide additional accuracy. IBFEM was used to simulate a divertor monoblock mock up, where it was found that a region of delamination existed on the CFC Cu interface. Predictions showed that if this was aligned unfavourably it would increase thermal gradients across the component thus reducing lifespan. As this was a feature introduced in manufacturing it would not have been accounted for without IBFEM.The technique developed in this work has broad engineering applications. It could be used similarly to accurately model components in conditions unfeasible to produce in the laboratory, to assist in research and development of component manufacturing or to verify commercial components against manufacturers’ claims.

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Hutten, Victoria Elizabeth. "Process Modeling of Thermoplastics and Thermosetting Polymer Matrix Composites (PMCs) Manufactured Using Fused Deposition Modeling (FDM)." University of Dayton / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1513073294210094.

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Garrett, Joseph Daniel. "Experimentation of Mode I and Mode II Fracture of Uni-Directional Composites and Finite Element Analysis of Mode I Fracture Using Cohesive Contact." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1670.

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As the use of fiber-reinforced composites has increased over the decades, so has the need to understand the complexity of their failure mechanisms as engineers seek to improve the damage tolerance of composite laminated structures. One of the most prevalent and limiting mode of failure within composite laminates is delamination, since it not only reduces a structures stiffness and strength, but can be very difficult to detect without the use of special non-destructive equipment. Industry testing organizations have utilized several fracture tests in order to characterize the fracture toughness of composite materials under different loading conditions. For this research, ASTM D5528, ASTM D7905 & 4ENF tests were performed to evaluate the fracture resistance of uni-directional pre-preg laminates; the 4ENF was used to compare its effectiveness as to ASTM D7905. Finite element methods such as the use of cohesive elements have been developed to simulate delamination within composite laminates. While there has been much work in evaluating the effectiveness of cohesive elements, very little exists within literature as to studying the success of cohesive surface contact for accurately modeling coupon level fracture testing. Cohesive contact interaction in Abaqus/Standard was used to simulate the mode I double cantilever beam (DCB) experiment of ASTM D5528. Cohesive contact was found to accurately and efficiently model DCB testing as the critical load- displacement values and steady state fracture agreed with experimental data. A parametric study was performed and found that cohesive contact was less sensitive in varying key model parameters than that commonly expected of cohesive elements.

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McGee, Caleb. "NUMERICAL EVALUATION OF ADHESIVE JOINTS IN COMPOSITE STRUCTURES USING FEA." OpenSIUC, 2015. https://opensiuc.lib.siu.edu/theses/1743.

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The increasing use of composite materials in many industries such as aerospace, automotive, and civil industries has increased the need for the development of effective techniques to detect defects in the bondlines of adhesive joints in composite structures. Currently, composite structures used in commercial applications such as modern aircraft use mechanical fasteners in redundancy to adhesive bonds to ensure structural integrity due to a lack of methods to reliably detect defects in the bondline of composite structure. As such, this thesis facilitates the development of nondestructive evaluation techniques for detecting bondline defects by using finite element (FE) modeling to simulate the effects of disbond defects caused by contamination of the bondline. These models were developed for single-lap joint specimens made of metal, composite, and dissimilar materials (metal bonded with composite) with contamination induced disbonds. The created FE models were used to generate whole-field strain data for single-lap joints under tensile loading. This generated strain data was then used to provide a model for evaluating and interpreting experimental strain measurements captured by digital image correlation (DIC). Finally, conclusions were drawn outlining the observed capability of strain measurement in the evaluation of bondline contamination in single-lap joints.

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Rodriguez, George IV. "Finite Element Modeling of Delamination Damage in Carbon Fiber Laminates Subject to Low-Velocity Impact and Comparison with Experimental Impact Tests Using Nondestructive Vibrothermography Evaluation." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1583.

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Carbon fiber reinforced composites are utilized in many design applications where high strength, low weight, and/or high stiffness are required. While composite materials can provide high strength and stiffness-to-weight ratios, they are also more complicated to analyze due to their inhomogeneous nature. One important failure mode of composite structures is delamination. This failure mode is common when composite laminates are subject to impact loading. Various finite element methods for analyzing delamination exist. In this research, a modeling strategy based on contact tiebreak definitions in LS-DYNA®was used. A finite element model of a low-velocity impact event was created to predict delamination in a composite laminate. The resulting delamination relative size and shape was found to partially agree with analytical and experimental results for similar impact events, while the force-time plot agreed well with experimental results. A small difference in contact time in the simulation compared to experimental testing is likely due to the omission of composite failure modes other than delamination. Experimental impact testing and subsequent vibrothermography analysis showed delamination damage in locations shown in previous research. This confirmed the validity of vibrothermography as a nondestructive evaluation technique for analyzing post-impact delamination.

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"Design Optimization of Laminated Composite Structures Using Explicit Finite Element Analysis." Master's thesis, 2014. http://hdl.handle.net/2286/R.I.26869.

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abstract: Laminated composite materials are used in aerospace, civil and mechanical structural systems due to their superior material properties compared to the constituent materials as well as in comparison to traditional materials such as metals. Laminate structures are composed of multiple orthotropic material layers bonded together to form a single performing part. As such, the layup design of the material largely influences the structural performance. Optimization techniques such as the Genetic Algorithm (GA), Differential Evolution (DE), the Method of Feasible Directions (MFD), and others can be used to determine the optimal laminate composite material layup. In this thesis, sizing, shape and topology design optimization of laminated composites is carried out. Sizing optimization, such as the layer thickness, topology optimization, such as the layer orientation and material and the number of layers present, and shape optimization of the overall composite part contribute to the design optimization process of laminates. An optimization host program written in C++ has been developed to implement the optimization methodology of both population based and numerical gradient based methods. The performance of the composite structural system is evaluated through explicit finite element analysis of shell elements carried out using LS-DYNA. Results from numerical examples demonstrate that optimization design processes can significantly improve composite part performance through implementation of optimum material layup and part shape.
Dissertation/Thesis
Masters Thesis Civil and Environmental Engineering 2014

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Boriek, Aladin Mohamed. "Modeling of setting stresses in particle-reinforced polymer composites using finite element analysis." Thesis, 1990. http://hdl.handle.net/1911/16321.

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This work uses three-dimensional Finite Element Analysis (FEA) to investigate the effect of geometric arrangement of particulate reinforcement in highly filled polymer composites (such as polymer concrete) on the setting stresses that develop in these materials during cure due to resin shrinkage during polymerization. These composites were initially modeled by systems reinforced with spherical particles packed in simple cubic (SC) and face-centered cubic (FCC) arrangements within the polymer matrix. A pronounced decrease in setting stresses was observed in the FCC system, which has a greater aggregate to resin ratio and more of resin domains per unit cell. A hexagonal-close-packed arrangement of hexagonal, prism-shaped aggregate was also analyzed and found to develop higher stresses, indicating that aggregate shape has an effect on setting stresses. A second set of models investigated the effect of size gradation and geometric arrangement of spherical reinforcing particles on setting stresses. The maximum stresses occur at the particle-resin interface, underlining the importance of resin/aggregate adhesion. Reduction of setting stresses by a factor of two was observed in systems with efficient packing, achieved with proper size gradation and close-packed geometry. A microstructural model for a polymer composite system based on a fairly random arrangement (FRA) of aggregate particles was also developed. This model gives a realistic representation of actual particle reinforced polymer composites. FEA results were used to develop an empirical equation for maximum setting stresses for Particle reinforced polymer composites. A probabilistic model for the distribution of voids in polymer composites was developed by solving a non-linear constrained optimization problem. The probability distributions of voids was used with a specially developed algorithm to generate the voids distributions in specific composites. The effect of voids on setting stresses in FRA models was discussed. In polymer composites voids tend to act as stress relief. This effect is more pronounced in poorly packed systems. This study provides an understanding of setting stress distribution in polymer composites. This work provides guidelines for optimizing the amount, shape and particle size distribution of the reinforcing aggregate in polymer composites so as to minimize setting stresses, thus leading to composites with significantly enhanced strength.

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Dissertations / Theses on the topic 'Finite element analysis of composites using Abaqus'

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