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1
Modenese, Luca. "Biomechanics, musculoskeletal modelling, hip joint loads prediction, muscle force estimation". Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/39476.
Testo completoAbstract (sommario):
A musculoskeletal model of the lower limb has been implemented and assessed in order to be used as a predictive tool to quantify the hip contact force (HCF) vector acting between the femoral head and the pelvic acetabulum. The model is based on a published anatomical dataset, which has been critically revised and extended. The HCFs obtained through the model have been assessed at multiple levels of detail against measurements from instrumented prostheses from a publicly available dataset. In the first instance, a direct comparison has been undertaken in order to verify predicted HCF magnitudes close to the measured and muscle recruitment consistent with electromyographic activation profiles reported in the literature. Secondly, a trend validation was performed to ensure the correct behaviour of the model when the same daily living task (level walking) was performed with different modalities. Finally, a falsification of the model was performed by challenging it to predict the exact components of the measured hip contact forces for both level walking and stair climbing. The closest achievable predictions were also calculated, together with the accuracy of a conventional use of the model not exploiting a priori knowledge of the joint contact forces. Once the assessment of the model was completed, a dataset of anthropometric, kinematic and kinetic data was collected on eight young healthy subjects performing daily living activities. As a demonstration of the potential use of the dataset, a subject specific model was generated and used to estimate HCF direction and magnitude for level walking and stair climbing, the same activities investigated during model validation. The model was further extended in order to include the upper part of the body and potentially analyze full body kinematics and kinetics. A further modified version of the model was finally developed in order to be used in finite elements analyses or more generally in applications requiring equilibrated sets of muscle and joint forces acting on a bone structure, as the highly discretized representation of the muscles makes the model particularly suitable for this kind of use. The developed model has been implemented in the open source software OpenSim and is freely available for download and use in research.
2
Yaghin, Mohammad Ali Lotfollahi. "Joint probabilities of responses to wave induced loads on monohull floating offshore structures". Thesis, Heriot-Watt University, 1996. http://hdl.handle.net/10399/687.
Testo completo
3
Gutierrez-Franco, Juan. "THE EFFECTS OF OBESITY ON RESULTANT KNEE JOINT LOADS FOR GAIT AND CYCLING". DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1624.
Testo completoAbstract (sommario):
Osteoarthritis (OA) is a degenerative disease of cartilage and bone tissue and the most common form of arthritis, accounting for US$ 10.5 billion in hospital charges in 2006. Obesity (OB) has been linked to increased risk of developing knee OA due to increased knee joint loads and varus-valgus misalignment. Walking is recommended as a weight-loss activity but it may increase risk of knee OA as OB gait increases knee loads. Cycling has been proposed as an alternative weight-loss measure, however, lack of studies comparing normal weight (NW) and OB subjects in cycling and gait hinder identification of exercises that may best prevent knee OA incidence. The objective of this work is to determine if cycling is a better weight-loss exercise than gait in OB subjects as it relates to knee OA risk reduction due to decreased knee loads. A stationary bicycle was modified to measure forces and moments at the pedals in three dimensions. A pilot experiment was performed to calculate resultant knee loads during gait and cycling for NW (n = 4) and OB (n = 4) subjects. Statistical analyses were performed to compare knee loads and knee angles, and to determine statistical significance of results (p < 0.05). Cycling knee loads were lower than gait knee loads for all subjects (p < 0.033). OB axial knee loads were higher than NW axial knee loads in gait (p = 0.004) due to the weight-bearing nature of gait. No differences were observed in cycling knee loads between NW and OB subjects, suggesting cycling returns OB knee loads and biomechanics to normal levels. The lack of significant results in cycling could be due to the small sample size used or because rider weight is supported by the seat. Limitations to this study include small sample size, soft tissue artifact, and experimental errors in marker placement. Future studies should correct these limitations and find knee joint contact force rather than knee resultant loads using v EMG-driven experiments. In conclusion, cycling loads were lower than gait loads for NW and OB subjects suggesting cycling is a better weight-loss exercise than gait in the context of reducing knee OA risk.
4
Simon, Joshua Cameron. "Response and Failure of Adhesively Bonded Automotive Composite Structures under Impact Loads". Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/34881.
Testo completoAbstract (sommario):
An experimental technique for conducting low speed impact of adhesively bonded automotive composite joints is presented. Based on the use of a modified drop tower, mode I, II, and mixed mode values for critical energy release rate were determined for a composite/epoxy system and used to create a fracture failure envelope. Because load measurements become erratic and unreliable at higher test rates, displacement-based relationships were used to quantify these energy release rates. Displacement data was collected with an imaging system that utilized edge detection to determine displacement profiles, end displacements, and opening displacements where applicable. Because of the resolution of the image-based approach used, determining crack length experimentally was extremely difficult. As a result, numerical methods were developed to objectively determine the crack length based on the available experimental data in mode I, II, and mixed mode I/II configurations.
This numerical method uses a nonlinear fit to determine mode I crack lengths and a theoretical model based on cubic equations for mode II and mixed-mode I/II, where the coefficients of the equations are determined by using both boundary and transition conditions that are a result of the test setup. A double cantilever beam (DCB) geometry was chosen to collect mode I data, an end-loaded split (ELS) geometry was used for mode II, and a single leg bend (SLB) geometry was used for mixed-mode I/II. These geometries were used to determine the fracture characteristics of adhesively bonded automotive composites to create fracture failure envelopes as well as provide mode I, II, and mixed-mode I/II data to be used in finite element models.
The chosen adhesive exhibited unstable, stick-slip crack growth, which resulted in very few data points being collected from each static DCB specimen as well as drastic drops in energy release rate between initiation and arrest points. Unstable growth also created issues in dynamic testing, as data points surrounding these "stick-slip" events were lost due to the insufficient sampling rate of the available imaging system.
Issues also arose with differences between thick and thin composite adherend specimens. These differences could result from additional curing in thick adherend composite specimens due to the adherends retaining heat. DSC testing was conducted on uncured adhesive using a 2, 5, and 10 minute hold at the cure temperature, and significant additional curing was observed between the two and five minute cures. Due to the difference in relative stiffness between the 12 and 36 ply composite, the local loading rate at the crack tip was lower in the 12 ply adherends, possibly allowing for a larger plastic zone and thus a higher energy release rate. As a result, tests were conducted on 36 ply composite specimens at rates of 1 mm/min and 0.1 mm/min to determine if there were loading rate effects. This testing showed that higher initiation energy relase rates were found at the lower test rate, thus reinforcing the local loading rate theory.
Due to issues with plastic deformation in aluminum adherends, mode II and mixed-mode I/II data were collected using only composite adherends. Only one data point was collected per specimen as the crack propagated directly into the composite after initiating from the precrack, thus multiple tests were conducted to collect sufficient data for constructing a failure envelope.
Once mode I, II and mixed-mode I/II fracture data was collected, a fracture failure envelope was created. This failure envelope, combined with a predetermined factor of safety, could provide some of the necessary tools for design with this adhesive/composite system.Master of Science
5
Mohamadzadeh, Milad. "Analysis of Metal Plate Connected Wood Truss Assemblies under Out-of-Plane Loads". Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/50271.
Testo completoAbstract (sommario):
In 2012, falls from elevation in construction industry represented 36% of the total fatalities. The Occupational Safety and Health Administration requires workers to use fall protection systems where workers are 6 feet or more above a lower level. Anchors for fall protection systems attached to roof trusses may cause out-of-plane loading on these structures. Metal plate connected wood trusses (MPCWT) are not designed to carry out-of-plane loads and MPCWT performance under these loads are not evaluated in the design process.
The goal of this research is to model and analyze MPCWT assemblies under out-of-plane loads. The rotational stiffness of truss-wall connections, and truss bracing elements are included in the structural component model. Previous experimental data of fall arrest anchor loading were used for model validation. A parametric study considering loading location, joint stiffness and dimension of trusses was conducted.
The structural analog of the MPCWT assemblies were found to have first truss deflections within 4% difference, thereby the models were validated. From parametric study results, the load location was not changed the ultimate deflection in the truss assembly by maximum value of 9%. Out-of-plane joint stiffness was the parameter that caused a large difference in the deflection results, when the joists were assumed as either rigid or simple connections. The rotational stiffness of lateral and diagonal bracing should be included as model inputs for the accurate representation of experimental behavior. Truss lengths increased the deflection at the top chord of the first truss in the assembly as truss width increased.Master of Science
6
Nolet, Vincent. "Analytical Methodology to Predict the Behaviour of Multi-Panel CLT Shearwalls Subjected to Lateral Loads". Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36999.
Testo completoAbstract (sommario):
The increasing demand for more sustainable construction has led to the development of new structural systems that include wood as building material. Cross laminated timber (CLT) has been identified as a potential system to address this need and to provide alternative options in the range of low- to medium-rise construction. The appeal in using CLT as a shearwall is driven by the combination of the rigid panels and small dimension fasteners, which allows for significant energy dissipation in the structure. However, there is currently no reliable analytical model to accurately predict the behaviour of multi-segment CLT shearwalls.
The current study aims to develop an analytical model capable of predicting the elastic and plastic phases associated with the behaviour of multi-panel CLT shearwalls. The model describes the wall behaviour as a function of the connectors’ properties in terms of stiffness, strength and ductility. This dependency means that the only input required in the model is the behavioural parameters of the connections. The proposed model contains six cases with a total of 36 different failure mechanisms. Two final wall behaviours were developed, and it was found that behaviour (i.e. single wall) could be achieved if the yielding in the hold-down occurred prior to yielding in the panel joints. Inversely, the other behaviour (i.e. coupled panels) was achieved if the yielding in the vertical joint occur prior to yielding in the hold-down. The analytical model was validated using a numerical model, and the results of the comparison showed very close match between the two models.
The study proposed simplified design provisions with the aim to optimize the walls ductility (CP behaviour) or strength and stiffness (SW behaviour).
7
Coombs, Matthew T. "Development of an experimental method to identify structural properties of the intervertebral joint after spine staple implantation under simulated physiologic loads". University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1322052236.
Testo completo
8
Hoffmann, Daniel E. "Ex Vivo Biomechanical Evaluation of the Canine Cranial Cruciate Ligament Deficient Stifle with Varying Angles of Stifle Joint Flexion and Axial Loads After Tibial Tuberosity Advancement". The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1243981690.
Testo completo
9
Sánchez, Tizapa Sulpicio. "Experimental and numerical study of confined masonry walls under in-plane loads : case : guerrero State (Mexico)". Phd thesis, Université Paris-Est, 2009. http://tel.archives-ouvertes.fr/tel-00537380.
Testo completoAbstract (sommario):
This research work proposes methods to rises the resistance and to evaluate the behavior of confined masonry walls built from clay solid bricks. These elements are widely used in Guerrero State (México) to build masonry structures, which should resist high lateral loads because of the serious seismic hazard. Therefore, a large experimental program to evaluate the mechanical properties of bricks and masonry currently required in the design process and masonry analysis was developed. To rises the masonry resistance and to counteract the influence of the compressive strength of the pieces on the masonry behavior, a high compressive strength mortar and a metallic reinforcement inside the joints were used. With respect to referenced values of the mechanical properties, some were similar and others were twice bigger. In this country zone, the first three tests under lateral load on full-scale confined masonry walls built from clay solid bricks were carried out in order to evaluate its behavior. A reinforcement composed by metallic hexagonal mesh-mortar coat was placed on the faces of two walls to rise or to restore the resistance. The walls showed good behavior and the reinforcement had adequate structural efficiency. Numerical models of panels and walls built by using the experimental data evaluated the envelope resistance, the failure mode and showed the influence of the mechanical properties of the pieces and joints on the global behavior. Two models had metallic reinforcement inside the joints. In addition, a constitutive law of the masonry defined from experimental results allowed to elaborate a simple model, which results were concordant with respect to the experimental results and similar to those calculated by complex models. Finally, two simplified models to evaluate the resistance of confined masonry walls by considering the failure plane on the wall diagonal were developed. One supposes the masonry failure by shear effect and the other supposes the masonry failure by induced tension. The ratio theoretical resistance vs. experimental resistance was adequate for walls built from different materials and tested under different loads, which had ratio Height/Length ranging from 0.74 to 1.26
10
Lemos, Fernando de Aguiar. "Desenvolvimento de um programa de análise de imagens radiológicas de membros inferiores com osteoartrite de joelho a partir de parâmetros biomecânicos funcionais". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/29252.
Testo completoAbstract (sommario):
A osteoartrite (OA) de joelho é uma doença multifatorial que acomete pessoas a partir da terceira década de vida, mas com maior incidência em idosos. Sua classificação é feita baseado em parâmetros clínicos e qualitativos durante uma intervenção médica. Nos casos mais avançados, a cirurgia de artroplastia de joelho envolve não apenas a substituição da articulação por uma prótese, mas também o realinhamento dos segmentos do membro inferior. Nesse caso há a necessidade de uma abordagem mais quantitativa na busca do reposicionamento desta articulação em relação ao eixo de suporte da carga corporal (ESCC). O objetivo deste estudo foi desenvolver uma metodologia de análise que possibilitasse quantificar uma série de parâmetros estruturais e funcionais a partir de imagens da raios-X em sujeitos saudáveis, assintomáticos para OA e em sujeitos com diagnóstico de OA de joelho. Este estudo utilizou-se da classificação adotada por Dejour (1991) para a classificação dos sujeitos em grupos com diferentes graus de OA. A amostra foi constituída de sujeitos de 25 a 80 anos com níveis de grau 1, grau 2 e grau 3 de OA. Além da classificação nos graus, os sujeitos foram separados pela presença ou não de dor em assintomáticos (OA sem dor) e sintomáticos (OA com dor). Imagens de raios-X foram obtidas do membro inferior dos sujeitos. Previamente à obtenção das imagens, um sistema de calibração foi construído com o objetivo de identificar possíveis erros de medidas e corrigi-los. Além disso, o sistema de calibração também foi utilizado na definição exata da metodologia a ser utilizada na obtenção dos exames radiográficos a fim de que a quantificação dos parâmetros estruturais e funcionais de cada membro inferior não apresentasse fatores intervenientes que pudessem mascarar os resultados obtidos de cada imagem digital, possibilitando também a comparação entre os indivíduos. Após a identificação dos fatores de correção das imagens digitais, um programa foi desenvolvido na plataforma Matlab para a identificação das variáveis geométricas dos membros inferiores. Além disso, também foi desenvolvida uma rotina matemática que permitiu calcular, por meio da de decomposição de vetores de força, as cargas que atravessavam cada articulação do joelho. Com estas informações foi possível comparar as variáveis geométricas dos membros inferiores entre os diferentes níveis de OA e também observar por meio de três modelos matemáticos qual a influência destas variáveis no mínimo espaço intra-articular medial (MEIAM), na força no compartimento medial (FCM) e nas estruturas contra-laterais a este compartimento, como o ligamento colateral lateral e trato iliotibial, neste trabalho denominados de força P. Os principais resultados obtidos no presente estudo foram: (1) o desenvolvimento de uma metodologia de calibração de imagens digitais capaz de reduzir os efeitos da ampliação da imagem, corrigindo os valores ampliados aproximando-os dos valores reais; (2) Foi observado que o desalinhamento dos membros inferiores avaliado pelo ângulo que representa a relação entre o quadril, joelho e tornozelo (QJT) tem influência na OA de joelho, assim como o ângulo entre os platôs condilares do fêmur e da tíbia (PC). Visto que quanto maior estes ângulos, menor o mínimo espaço intra - articular medial (MEIAM) e maior os graus de OA. 3) Quando avaliado as variáveis geométricas dos membros inferiores em um teste de regressão linear múltipla, para saber a influência na força do compartimento medial (FCM), na força do ligamento colateral lateral e tracto iliotibial (força P) e no MEIAM, o QJT teve maior poder explicativo tanto para as cargas como o MEIA, confirmando a teoria mecânica. Entretanto o ângulo do colo do fêmur (ACF), apesar de uma baixa participação (6%) que mostrou um grau de importância significativo nos modelos de carga do compartimento e do MEIAM. Assim, embora nós saibamos que os segmentos inferiors ajustam-se mecanicamente em relação a carga, foi observado que o desalinhamento dos membros inferiores é um fator de risco mais importante entre todas as variáveis para o desenvolvimento da OA.Knee osteoarthritis (OA) is a multifactorial disease that affects people from the third decade of life, but with higher incidence in the elderly. Its classification is based on clinical and qualitative parameters during a medical intervention. In more advanced cases of OA, knee arthroplasty involves not only joint replacement with prosthesis, but also the realignment of the lower limb segments. In this case, there is a need for a more quantitative approach in the pursuit of the joint repositioning in relation to the load bearing axis (LBA). The aim of this study was to develop a methodology that would enable the quantification of a number of structural and functional parameters, using X-ray images, in healthy subjects, asymptomatic for OA and subjects diagnosed with knee OA. This study used the classification adopted by Dejour (1991) to classify the subjects into groups with different degrees of OA. The sample consisted of subjects between 25 and 80 years old, classified with levels 1, 2 and 3 of OA. Besides this classification, subjects were separated by the presence or absence of pain into asymptomatic (OA without pain) and symptomatic (OA with pain). Radiographic images of the lower limb were obtained of the subjects. Prior to obtaining the images, a calibration system was built to identify possible measurement errors and correct them. In addition, the calibration system was also used to define the exact methodology to be used to obtain the images, so that the quantification of structural and functional parameters of each lower limb did not present intervening factors that might mask the results, allowing also the comparison between individuals. After identifying the correction factors of the digital images, a Matlab routine was developed to identify the geometric variables of the lower limbs. In addition, this routine also allowed the calculation, through the decomposition of force vectors, of the loads that cross each knee joint. With this information, it was possible to compare the geometric variables of the lower limbs between different levels of OA and also observe, by means of three mathematical models, the influence of these variables on the medial intra-articular minimum space, on the force in the medial compartment (FMC) and on the contra-lateral structures in this compartment, such as the lateral collateral ligament and the iliotibial tract, called, in this work, P force. The main results of this study were: (1) the development of a calibration methodology for digital images capable of reducing the effects of image magnification, adjusting the values closer to real values; (2) the observation that the misalignment of the lower extremities, evaluated by the angle that represents the relationship between hip, knee and ankle (HKA), has an influence on knee OA, as well as the angle between the condyle plateaus of the femur and the tibia. The larger this angle is, smaller is the medial intra-articular minimum space, and higher are the levels of OA; (3) when evaluating the geometric variables of the lower limbs in a multiple linear regression test, to identify the influence of these variables on the force of the medial compartment (FMC), on the force of the lateral collateral ligament and the iliotibial tract (indicated here as P force) and on the MIAMS it was possible to observe that the HKA showed larger explanatory power for the loads as the MIAMS, confirming the mechanical theory. However, for the angle of the femoral neck (AFN), despite a lower power to explain the dependant variables (only 6%), it still showed a significant importance in the load compartment models and MIAMS. Thus, although we know that the segments adapt or mechanically adjust in response to load, it seems that the lower limb segments alignment is the most important factor amongst all variables as a risk factor for the development of knee OA.
11
Sahboun, Salahaddin. "V-band joint torsional load capacity". Thesis, University of Huddersfield, 2015. http://eprints.hud.ac.uk/id/eprint/28321/.
Testo completoAbstract (sommario):
This research thesis presents an analysis of the torsional loads on V-band clamps. In some applications, the relative rotational movement of the flanges connected by V-band clamps can result in catastrophic system failure. The ability to understand the factors impacting on torsional load capacity is therefore essential. In this research project, a theoretical model of a V-band joint subjected to torsional loads was developed. This model is used to identify those parameters that will impact on the joint’s reliability. An experimental investigation was conducted to validate a theoretical model using a newly developed test rig. The development and features of this test rig are presented in this report. This experimental investigation also allowed the impact of those parameters that are difficult to control, to be determined. A total of three V-bands were used with different diameters but nominally identical cross sections were studied. In the research results, the initial slip point between flanges and the V-band clamp was identified by experimentation within this research project. Different sizes of Vbands were used under boundary conditions and loads. From the simulation results it was determned that the friction effect on the V-band depends on the size of the V-band. For the largest size of V-band, there was moderate correlation of the experimental and theoretical results. For the smallest size, the results suggest that with band tightening, flange contact is localised, rather than being throughout the band’s entire circumference. The research demonstrated the significant relevance of the band and flanges’ contact points and the coefficient of friction, especially that between the flanges, on the V-band clamp’s theoretical torsional load capacity.
12
Huťka, Pavel. "Deformačně napěťová analýza TEP kyčelního kloubu – typ Santori". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-378901.
Testo completoAbstract (sommario):
Submitted Diploma thesis deals with stress-strain analysis of deformation proximal end of femur with applied total hip joint endoprosthesis (replacement) – shortcut type. To identify deformation and tensity (stress) was used computational simulation by method of final elements. Have been created two computational models TEP- type Santori and type DePuy Proxima. Geometry model Santori was created on low level model geometry through the use of X-ray photograph. Principle of geometry model type DePuy Proxima was real Femoral stem endoprosthesis which was scanned on scanner ATOS. Geometry of both these replacements were set up in program Rhinoceros 4.0 and then execute in program CatiaV5R17. Data for geometry model of femur were gained from CT chains. Material model of femur have been crated in two variants. The first one looks at structure bone tissues and the second one were created by Gruen´s zones. Femoral Stem was weighted by static equivalent resultant force acting in hip joint. Computational model of system and self solution, including depiction results, was done by ANSYS Workbench 11.0 for four model variants.
13
Rýdel, Jiří. "Deformačně napěťová analýza TEP kyčelního kloubu – typ Mayo". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-378907.
Testo completoAbstract (sommario):
This diploma thesis deals with hip endoprothesis, primarily with endoprothesis conservative Mayo. A part of this paper considers a study aimed at an anatomy, types and modern trends in endoprothetic. On the basis of this study, gained CT data and the help of systems Ansys Workbench, Rhino Ceros and Catia there was made a model of proximal part of femur and TEP Conservative Mayo. A computational model was build up afterwards, which was used for a stress-train analysis.
14
Söderberg, Johan. "A finite element method for calculating load distributions in bolted joint assemblies". Thesis, Linköpings universitet, Mekanik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-81739.
Testo completoAbstract (sommario):
Bolted joints are often the most critical parts with respect to fatigue life of structures. Therefore, it is important to analyze these components and the forces they are subjected to. A one-dimensional nite element model of a bolted joint is created and implemented as a program module in the Saab software `DIM', together with a complete graphical user interface allowing the user to generate the structure freely, and to apply both mechanical and thermal loads. Available methods for calculating fastener exibility are reviewed. The ones derived by Grumman, Huth and Barrois are implemented in the module, and can thus be used when dening a geometry representing a bolted joint assembly. Investigations have shown that it cannot be said that either method is generally better than the other. Calculated properties of interest include the fastener forces, plate bearing and bypass loads, and - for simpler geometries without thermal loads - the load distribution between rows of fasteners. The program is fully functional and yields numerically accurate results for the most commonly used joints where fasteners connect two or three plates each. It has limited functionality on geometries with fasteners connecting four or more plates and for a certain loading combination also for three plates, due to the tilting of the fasteners not being accounted for in the model for these cases. Also, there is no explicit method available for nding an accurate value for the fastener exibility for these, less common, joint structures.
15
Angelakos, Bill. "The behavior of reinforced concrete knee joints under earthquake loads". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0003/NQ41091.pdf.
Testo completo
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Dale, Kenneth William 1971. "Behaviour of tubular connections under variable repeated loads". Monash University, Dept. of Civil Engineering, 2001. http://arrow.monash.edu.au/hdl/1959.1/8848.
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17
Carroll, Jeffery D. "Withdrawal and combined load capacity of threaded fastener wood joints /". This resource online, 1988. http://scholar.lib.vt.edu/theses/available/etd-04122010-083654/.
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Vidová, Miriama. "Objekt střediska živočišné výroby". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-391888.
Testo completoAbstract (sommario):
My diploma theisis is focused on design and assessment of structural systém of industrial building in tended for livestock farming. The design is processed in two options. Both oft hem has the same dimensions but cross sections of the supporting elements are changed. Floor plan of the first part is a rectangular shape, dimension is 29,28 m x 24,8 m. Floor plan of the second part is a rectangular shape, dimension is 161,18 m x 46,8 m. Slope of saddle roof is 18°.
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Cotter, Joshua Allan. "The Effect of Squat Load and Depth on Patellofemoral Joint Kinetics". The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1243606700.
Testo completo
20
Cunningham, Ronald. "Effects of joint continuity on tapered member steel portal framed structures". Thesis, Heriot-Watt University, 1987. http://hdl.handle.net/10399/1051.
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21
Cruz, Helena Maria Pires. "Nailed timber joints subjected to alternating load cycles". Thesis, University of Brighton, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357016.
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Srinivasan, Shiva. "Characterization of stresses induced in doweled joints due to thermal and impact loads". Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=2186.
Testo completoAbstract (sommario):
Thesis (M.S.)--West Virginia University, 2001.Title from document title page. Document formatted into pages; contains x, 114 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 108-113).
23
Sander, Jason Andrew. "Mechanical-Empirical Performance of U.S. 50 Joint Sealant Test Pavement". University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1176222025.
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Carroll, Jeffrey D. "Withdrawal and combined load capacity of threaded fastener wood joints". Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/42043.
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Ni, Chun. "Behavior of nailed timber joints under reversed cyclic load". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq23869.pdf.
Testo completo
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Leen, Sean B. "Elastic-plastic generalised load-displacement prediction for tubular joints". Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287266.
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27
Hong, Jiazheng. "A Semi-Analytical Load Distribution Model of Spline Joints". The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1426110670.
Testo completo
28
Geffre, Chris. "In vivo evaluation of polymer implants for cartilage regeneration and joint load monitoring". Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/195860.
Testo completoAbstract (sommario):
Osteoarthritis, which affects over 21 million people and costs the US $61 billion/yr, is devastating the US population and taxing the health care system. These numbers will increase exponentially as the population ages. It is reported that previous trauma to cartilage resulting in focal chondral defects progresses to osteoarthritis if treatment is delayed or unsuccessful. Current treatment modalities for focal chondral defects have had variable success rates. As such scaffold based therapies in combination with tissue engineering are being developed as an alternative therapy for focal chondral defects. One important area of research to be addressed for these therapies to be successful is rapid integration of native tissue with the implant. An advantage of using scaffold based therapies is that scaffolds provide a stable surface for tissue to grow on and integrate with the existing tissue. In addition, there is the opportunity to use scaffolds for measuring joint loading. These measurements are crucial for a better understanding of the loading environment leading to osteoarthritis as well as for development of rehabilitation regimens when tissue engineering is used to treat defects. It is the goal of this research to determine if mimicking the native trabecular bone structure can be utilized to promote rapid bone ingrowth into implants and to determine whether these implants can be used to directly measure in vivo joint loads. To address the goals of this study, polybutylene terephthalate scaffolds were designed and then built using a fused deposition modeling system. Two different scaffold designs were utilized to determine if mimicking bone structure results in improved bone ingrowth. One scaffold was a biomimetic scaffold that replicated the trabecular bone structure and the other utilized a simple porous structure. These scaffolds were also equipped with strain gauges so that they could be used to monitor joint loading within the knee joint. The strain gauges were used in combination with implantable miniature radio transmitters to allow a fully internal measurement system to be used to determine joint loads during gait as well as other weight bearing activities. Using histology and μCT it was observed that the biomimetic scaffolds increased bone ingrowth into the scaffold over 500% compared to the simple porous scaffolds. These biomimetic scaffolds also increased bone growth in the areas adjacent to the scaffold. Additionally, it was demonstrated that these scaffolds when outfitted with strain gauges could measure axial joint loads occurring within the knee joint during various activities. It was noted that the temporal measurements were highly correlated with video analysis and that peak loads increased as a function of time post implantation. The ability of biomimetic scaffolds to increase bone ingrowth is important for anchoring the scaffold in place and allowing successful integration of tissue engineered cartilage with the native tissue. This will improve success rates of scaffold based tissue engineering therapies. The ability of implants to measure joint loads is crucial to developing a better understanding of osteoarthritis as well as improving rehabilitation protocols. Additionally, by monitoring the change in peak loads with time it will be possible to monitor the healing response at the implant site. Overall, this research demonstrates that polybutylene terephthalate scaffolds have the ability to be used in combination with tissue engineering constructs to treat focal chondral defects and are capable or providing direct in vivo loading measurements.
29
Owellen, Michael C. "Biotribology: The Effect of Lubricant and Load on Articular Cartilage Wear and Friction". Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36872.
Testo completoAbstract (sommario):
This paper presents a biotribological study on cartilage
wear and friction, using a system of cartilage-on-stainless
steel. This study is a part of the ongoing biotribology
research by Dr. Furey at the Virginia Polytechnic
Institute and State University.Two loads (65 N and 20 N) and three lubricants (saline reference, reference + hyaluronic acid, and bovine synovial fluid) were tested and evaluated using several analysis techniques. These techniques included wear analysis by hydroxyproline measurement, scanning electron microscopy (SEM), histologic sectioning and staining, numerical analysis of friction and specimen displacement data, and Fourier transform infrared (FTIR) analysis.
Biochemical wear analysis showed that, under high load, the saline reference generated the most wear, hyaluronic acid produced less wear, and bovine synovial fluid produced the least. Wear was sensitive to load with all three lubricants, but was not significantly affected by the lubricant under low load.
SEM photographs and histologic sections showed evidence of plowing and surface delamination, as well as another wear mechanism that produced wear markings perpendicular to the direction of sliding.
Opaque films remained on the polished stainless steel
disks after saline and hyaluronic acid tests, but not after
synovial fluid tests. FTIR analysis of these films, as
well as fresh and worn cartilage, showed that the cartilage
experienced chemical changes during sliding.
Master of Science
30
Zarco-GonzaÌlez, JoseÌ Carlos. "Analysis of damage progression in composite joints subjected to bearing and by-pass loads". Thesis, Oxford Brookes University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.432764.
Testo completo
31
Šandor, Peter. "Víceúčelová sportovní hala". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409834.
Testo completoAbstract (sommario):
The goal of my thesis is the design of a multipurpose sport hall in Litoměřice locality made in two separate variants. Objects ground plan dimensions are 38x38 meters and the height of the object is 16 meters. Used material is S235 steel and C20/25 concrete. The periphery and roof casing of the object is realized from sandwich panels. The carrying construction of the object is made from cross truss, oblong truss and from pillars. Thesis consists of assessing the carrying elements of the construction, selected details and drawing documentation.
32
Timko, Paul Daniel. "Finite Element Analysis of Unbraced Structural Wood I-Joists Under Construction Loads". Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/42527.
Testo completoAbstract (sommario):
The research summarized the experimental analysis and finite element modeling of the lateral and rotational response of unbraced wood composite I-joists to worker loads. All experimentation and modeling was conducted on simply supported I-joists varying from 11-7/8 inches to 14 inches in depth and 20 feet to 24 feet in length. I-joists were subjected to static and dynamic loads. The deflections of the top and bottom flanges, as well as the rotation, were measured or calculated at both one-half and one-quarter the span length. The overall goal of this project is to accurately model the lateral and rotational displacements caused by human load effects.
I-joists were first tested statically by subjecting each joist to a three point bending test, free from all lateral restraints. This test was necessary to prove that the performance of the joists was repeatable. Lateral and rotational stiffness of the joist were calculated at one-half and one-quarter of the span length. The static experimental tests results were statistically analyzed using an analysis of variance (ANOVA) test. The results from this analysis indicated no difference between repetitions of the same joist; however, the test did indicate that there was a significant difference between joists of the same manufacture and size. Dynamic testing was then conducted. Dynamic loads were induced by having test subjects traverse each I-joist. The resulting loads induced at the top and bottom flanges were recorded for use in the finite element model. The lateral deflections and induced loads were compared to the static weight of the test subject and analyzed with an ANOVA test. The results indicated an increase in both the induced load and resulting deflection with an increase in weight. The analysis also indicated an increase in load and deflection with a decrease in lateral and rotational joist stiffness.
The recorded load values from the dynamic test were used as inputs into a finite element model. The resulting lateral deflections of the midpoint and quarter point were generated. The rotation of the beam was calculated from the difference between the top and bottom flange. Experimental results and finite element model results were compared by calculating a running average of the error between the acquired data and the finite element model. The model was said to be valid until the average model error reached 10 percent of the maximum acquired test value. All six deflection readings were analyzed in this manner. The percent of beam at which the model no long represented the test data was determined for each data set. This point was averaged across all deflection readings of similar joists and across all data sets of the same joist type. The model predicted the 20 foot long 11-7/8 and 14 inch deep joists until 54.5 percent and 51.2 percent, respectively, of the beam completed by the test subject. However, the 24 foot long 11-7/8 inch deep joist was only accurate to 31.2 percent of the beam completed by the test subject.
Differences in peak values, and the time at which the peak values occurred were also analyzed using an ANOVA test. There was a significant difference between the peak values of the acquired test data and the deflections generated with the finite element model. However, there was no significance within the time that the peak values occurred between the model and experimental results.
A simplified pseudo dynamic analysis was conducted using a constant percentage of the test subject's static weight applied to the top and bottom flange. This approximation proved adequate for the lateral displacement and rotation of the 11-7/8 inch and 14 inch deep and 20 foot long I-joists. However, the model became un-conservative for the 11-7/8 inch deep and 24 foot I-joists.Master of Science
33
Lo, Clifford Fook Leong. "Behaviour and design of eccentrically loaded bolted connections". Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63986.
Testo completo
34
Fernandez, Mauricio. "Effects of Temperature and Creep on the Clamp-up Load in Hybrid Metal to Composite Bolted Joints". Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/FernandezM2008.pdf.
Testo completo
35
Korolija, Alexandra. "FE modeling of bolted joints in structures". Thesis, Linköpings universitet, Hållfasthetslära, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-81110.
Testo completoAbstract (sommario):
This paper presents the development of a finite element method for modeling fastener joints in aircraft structures. By using connector element in commercial software Abaqus, the finite element method can handle multi-bolt joints and secondary bending. The plates in the joints are modeled with shell elements or solid elements. First, a pre-study with linear elastic analyses is performed. The study is focused on the influence of using different connector element stiffness predicted by semi-empirical flexibility equations from the aircraft industry. The influence of using a surface coupling tool is also investigated, and proved to work well for solid models and not so well for shell models, according to a comparison with a benchmark model. Second, also in the pre-study, an elasto-plastic analysis and a damage analysis are performed. The elasto-plastic analysis is compared to experiment, but the damage analysis is not compared to any experiment. The damage analysis is only performed to gain more knowledge of the method of modeling finite element damage behavior. Finally, the best working FE method developed in the pre-study is used in an analysis of an I-beam with multi-bolt structure and compared to experiments to prove the abilities with the method. One global and one local model of the I-beam structure are used in the analysis, and with the advantage that force-displacement characteristic are taken from the experiment of the local model and assigned as a constitutive behavior to connector elements in the analysis of the global model.
36
Arnold, Stuart John. "Load transfer across cracks and joints in concrete slabs on grade". Thesis, Loughborough University, 2004. https://dspace.lboro.ac.uk/2134/7581.
Testo completoAbstract (sommario):
This research has investigated the behaviour of joints and cracks under single and multiple cycles of load. This provides an increased understanding of concrete slab on grade performance, enabling more effective design and monitoring procedures. Examination of the geometry of cracks and joints within concrete slabs on grade has demonstrated that the commonly assumed parallel formation is erroneous. Measurements using embedded strain gauges, coring and surface profile levelling have uncovered that a high percentage of joints will contain larger crack widths at the surface than at the base, caused by differential shrinkage. The opening itself is relatively linear; however, the top 50mm of the slab is prone to a higher gradient of movement due to the increased drying effect towards the surface. A series of deflection tests using a Falling Weight Deflectometer and Prima dynamic plate enabled slab response under load to be evaluated. Four sites were examined in total and correlations found between: load transfer, load step, edge cantilever and crack geometry. This produced valuable information regarding the influence of load transfer and crack width on the overall slab behaviour. Foundation voiding and crack face free slip was also shown to influence deflection magnitude. A small-scale test facility was developed for the assessment of deterioration in various 'V' shaped and parallel crack widths under high cycle loading. The data demonstrated that joint/crack failure contains four distinct phases of deterioration, each of which is controlled by a different mechanism. 'V' shaped cracks produced a much greater load transfer than that of a parallel crack with the incorporation of A142 mesh and steel fibres reducing differential displacement. Load magnitude and aggregate size were also shown to have significant effects. The value of reinforcement was found to assist with serviceability requirements, keeping displacement within acceptable levels and preventing the onset of serious degradation A finite element model was developed to enable the load transfer mechanism results from the laboratory test to be used in the assessment of full slab response. Simulations of field testing produced a series of lower bounds in respect to deflections and the associated response calculations. Theoretical behaviour of a typical slab was assessed with subbase support, joint stiffness, slab thickness and the incorporation of a subbase, found to be highly influential in reducing slab deflections. The three main sections of work comprising site data collection, laboratory testing and Finite Element modelling have been used together to provide a much greater understanding of the influence of cracks and joints. This has included the deterioration of cracks over time and an examination of how this and other site-based factors affect overall slab behaviour.
37
Kratochvil, Jan. "Asymptotic Analysis of the Load Transfer on Double-Lap Bolted Joints". Phd thesis, Techn. Univ., Studienbereich Mechanik, 2012. https://tuprints.ulb.tu-darmstadt.de/2997/1/Diss_Kratochvil.pdf.
Testo completoAbstract (sommario):
In this thesis, the complex potential method along with the method of compound asymptotic expansions is applied to the analysis of selected problems of plane elasticity related to double-lap bolted joints. The contribution to the thesis lies in the construction of several closed-form approximations of solutions to the considered problems.
After a brief introduction of the basic theoretical concepts in Chapter 2, a mathematical model of a double-lap bolted joint is presented in Chapter 3. A very simple model is chosen in order to make an analytical treatment possible. This model assumes the (generalised) state of plane stress in each of the plates and a simple sinusoidal distribution of contact pressure in the bolt-to-hole contact and leads mathematically to the first fundamental problem of the plane theory of elasticity.
In Chapter 4, a formal asymptotic solution of the first fundamental problem for an infinite plane or half-plane weakened by a finite number or an infinite symmetric array of small holes is derived. The relative hole radius plays the role of the small parameter. Three different governing partial differential equations are considered, namely the Laplace equation, the bipotential equation and a more general linear elliptic fourth-order partial differential equation with constant coefficients. An asymptotic expansion of the complex potentials is derived for each equation. It is uniformly valid in the whole domain, i.e. in the vicinity of each of the holes as well as in the far-field. The solution is summarised in form of algorithms for a computer algebra system and implemented in Mathematica. Furthermore, a fully parametrised finite element model of the considered problem has been created using the commercial FE Software Abaqus and its Python programming interface in order to verify the results in an independent way.
This general solution is in Chapter 5 applied to three types of problems. The first one is the problem of stress concentration on unloaded holes. Its purpose is to evaluate the capability of the method by means of simple examples where a sufficiently high number of terms of the asymptotic series can be generated. The second type of problems involves the compliance of an infinite row of pin-loaded holes. A closed-form approximate formula for the compliance of an infinite row of pin-loaded holes in an infinite isotropic plane and a half-plane is derived. This formula, as opposed to semi-empirical formulae commonly used in the industrial environment, correctly takes into account the contributions of the plane deformation of the plates to the overall compliance of the joint. Finally, the third type deals with the determination of the load distribution on both finite number of bolts as well as infinite rows of bolts. Closed-form approximations of the load distribution factor for these configurations are presented.
A certain problem related to the nature of the proposed solution is the convergence of the asymptotic series. As expected from the nature of the asymptotic solution, the discrepancy between the asymptotic solution and a reference numerical one is the smallest for small radii and with increasing radii, it generally increases. However, results with the presented order of approximation are sufficiently accurate in the technically relevant domain.
In the case of anisotropic material behaviour, the formulae describing the dependence on the material parameters are too complex for practical use even in the simplest situations such as stress concentration on a single hole in a half-plane. A certain simplification can be achieved by assuming strong orthotropy and performing a Taylor expansion in terms of the corresponding small parameter. It appears that such an expansion exhibits good convergence and can be therefore used also for moderately orthotropic materials. Unfortunately, it was not possible to obtain analytical results for infinite rows of holes in anisotropic plates because the proposed algorithm leads to infinite sums that cannot be be evaluated analytically.
38
Benatar, Michael A. "An Experimental Investigation of the Load Distribution of Splined Joints under Gear Loading Conditions". The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1460908970.
Testo completo
39
Borkowski, Larry John. "Effect of Manufacturing Tolerances on the Number of Load Carrying Fasteners in a Joint Subjected to a Shear Load: A Statistical Approach". Master's thesis, University of Central Florida, 1987. http://digital.library.ucf.edu/cdm/ref/collection/RTD/id/72687.
Testo completoAbstract (sommario):
University of Central Florida College of Engineering ThesisWithin the elastic range, the number of load-carrying fasteners in an interchangeable manufactured joint subjected to a shear load is dependent upon the following characteristics: 1. Material properties of the constituent parts in the shear joint. 2. Geometry of the shear joint. 3. Manufacturing tolerances of the constituent parts in the shear joint. 4. Number of fasteners in the shear joint. 5. Preload on the fasteners in the joint. 6. Static coefficient of friction between the joint surfaces. Neglecting the effects of preload and friction, the number of load-carrying fasteners is determined for a theoretical bolted joint design as a function of the remaining four (above) parameters. The analysis is accomplished by assuming all deformation in the constituent parts of the joint remain within the elastic range and then examining the stress-strain relationship existent in the shear joint. Based on simplifying assumptions, the total deflection is calculated and then, statistics are applied to the manufacturing tolerances of the constituent parts of the shear joint. The results suggest that plastic deformation occurs in all classically designed shear joints and the predicted number of load carrying fasteners using this analysis approach is in error. Suggestions for future research are presented.
M.S.
Masters
Engineering
Engineering
74 p.
vi, 74 leaves, bound : ill. ; 28 cm. + 1 computer diskette.
40
Blom, Arvid. "Speed dependent friction in bolt joints". Thesis, KTH, Maskinkonstruktion (Inst.), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-141687.
Testo completoAbstract (sommario):
Denna rapport undersöker hastighetsberoende friktionsbeteende i zinkpleterade 8.8 M12x1.75 skruvförband med en klämlängd på 82 mm och ett åtdragningsmoment på 120 Nm. Totalt 84 åtdragningar genomförs med nya skruvar, brickor och muttrar för varje åtdragning med utrustning tillhandahållen av Atlas Copco. All data importeras och analyseras i Matlab. Analysen visar att inom en standard avvikelse från medelvärdet kan klämkraften variera med så mycket som 90% beroende på var inom det 10-200 rpms hastighetsspannet skruven drogs åt. Vidare framgår även att restmomentet är mycket beroende av den hastighet som skruven drogs åt vid, med ett restmoment ~5 Nm över slutmomentet för 10 rpm och ~20 Nm över slutmomentet vid 200 rpm. En ursprunglig hypotes tas fram som antar att en utförlig modell av lastfördelningen i skruvensgänga och under skruvens skalle kan användas för att förutse skruvförbandets friktionsbeteende. Denna hypotes övergavs då mätresultat och analys visar att effekten av en förbättrad lastfördelningsmodell inte skulle märkas då spridningen i friktionen är för stor.This report examines the speed dependency of frictional behavior in zinc plated 8.8 M12x1.75 bolt joints with an 82 mm clamping length at a tightening torque of 120 Nm. A total of 84 test tightenings have been performed with new bolts, nuts and washers for each tightening. The tests are performed using equipment supplied by Atlas Copco and all data is imported and analyzed in Matlab. It is found that within one standard deviation of the mean value the clamping force can vary as much as 90% depending on where in the 10-200 rpm speed range the bolt is tightened. Furthermore it is concluded that the residual torque is also highly speed dependent, registering at ~5 Nm above the final torque at 10 rpm and ~20 Nm above at 200 rpm. An initial hypothesis was developed regarding the pressure distribution in the thread and under the bolt head in the hopes that better understanding and modeling of this aspect could help predict frictional behavior in the bolt joint. This hypothesis was abandoned after it is concluded that the impact of an improved pressure model would be much too small to be noticeable due to the already large scatter in frictional coefficients.
41
Ford, Catherine Mary. "The role of the meniscus in knee joint load transmission : a three-dimensional finite element study". Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/17306.
Testo completo
42
Bamberg, Christopher Ryan. "Lateral Movement of Unbraced Wood Composite I-Joists Exposed to Dynamic Walking Loads". Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/31977.
Testo completoAbstract (sommario):
The research summarized in this thesis is comprised of an experimental analysis of the mechanical behavior of a wood composite I-joist with different bracing configurations exposed dynamic walking loads. Three 16 in. deep GPI® 65 I-joists were simply supported and laid parallel to each other, while the bracing was attached to the top flange. Five different brace stiffnesses were used: zero stiffness (control), 1.2 lb/in., 8.5 lb/in., 14.0 lb/in. and infinitely stiff. Two different brace configurations were used: one-quarter of the span length (60 in.) and one third the span length (80 in.). The dynamic walking loads consisted of human test subjects attached to a safety platform walking across the I-joist at a designated pace. Experimental results for this research consisted of the I-joistâ s lateral accelerations, lateral displacements and twist. An Analysis of Covariance (ANCOVA) was used for the statistical analysis of the results and was performed for each measurement. The statistical analysis determined the effects of different bracing configurations, stiffnesses, measurement locations as well as test subjectsâ weight and occupation.
Test results and observed trends are provided for all test configurations. Lateral displacement and twist experienced the same trend throughout the experiment: as brace stiffness increased, lateral displacement and twist decreased. This correlated with basic beam theory and bracing fundamentals. It should be noted that as the stiffness increased, the effect on lateral displacement and twist response decreased.
However, the trend for lateral displacement and twist was not observed for the lateral accelerations. The 1.2 lb/in. brace stiffness had much larger lateral accelerations for the 60 in. brace configuration throughout the span and were also larger at the bracing point for the 80 in. brace configuration. This could have been due to the energy applied from the springs or a natural frequency of the I-joist system could have been reached during testing. However, the other four brace stiffnesses followed the same trend as the lateral displacements and twist.
In addition, this research demonstrates a method for the measurement of lateral buckling due to worker loads. The mitigation of lateral buckling can use appropriate bracing systems. The measurements of the change in lateral buckling behavior can be used to develop safety devices and ultimately ensure the protection of construction workers.
Master of Science
43
Wilke, Fabian [Verfasser]. "Load Bearing Behaviour of Grouted Joints Subjected to Predominant Bending / Fabian Wilke". Aachen : Shaker, 2014. http://d-nb.info/1049381440/34.
Testo completo
44
Li, Yantao. "Behaviour of moment-resisting multi-fastener joints subject to reversed cyclic load". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0035/MQ65502.pdf.
Testo completo
45
Boseman, Mark F. "Study of load transfer and fracture on composite-to-metal-wire joints". Thesis, Monterey, Calif. : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/March/09Mar%5FBoseman.pdf.
Testo completoAbstract (sommario):
Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, March 2009.Thesis Advisor(s): Kwon, Young W. "March 2009." Description based on title screen as viewed on April 23, 2009. Author(s) subject terms: butt joint, overlap joint, modified-wire-end-shape joint, finite element method, energy release rate, virtual crack closure method, fracture toughness, ansys. Includes bibliographical references (p. 43). Also available in print.
46
Rastogi, Naveen. "Load transfer in the stiffener-to-skin joints of a pressurized fuselage". Diss., This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-06062008-155607/.
Testo completo
47
Chastain, Patrick Alan. "Effects of load proportioning on the capacity of multiple-hole composite joints". Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/90922.
Testo completoAbstract (sommario):
This study addresses the issue of adjusting the proportion of load transmitted by each hole in a multiplehole joint so that the joint capacity is a maximum. Specifically two-hole-in-series joints are examined. The results indicate that when each hole reacts 50% of the total load, the joint capacity is not a maximum. One hole generally is understressed at joint failure. The algorithm developed to determine the load proportion at each hole which results in maximum capacity is discussed. The algorithm includes two-dimensional finite-element stress analysis and a failure criteria. The algorithm is used to study the effects of joint width, hole spacing, and hole to joint-end distance on load proportioning and capacity. To study hole size effects, two hole diameters are considered. Three laminates are considered: a quasi-isotropic laminate; a cross-ply laminate; and a 45 degree angle-ply laminate. By proportioning the load, capacity can be increased generally from 5 to 10%. In some cases a greater increase is possible.M.S.
48
Charlton, Zachary. "Innovative Design Concepts for Insulated Joints". Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/35509.
Testo completoAbstract (sommario):
The main goal of this research is to develop new and innovative designs for insulated rail joints for improved life cycle and higher cost effectiveness. The research focuses on using electrically insulating materials that replace the epoxy used in current bonded insulated joints. Insulated joints (commonly known as â IJsâ ) are widely used on railways to electrically insulate rail segments from each other, while mechanically connecting them together. The electrical insulation is necessary for accommodating track signals. The mechanical strength is needed to ensure the rail and IJs are able to withstand the vertical, longitudinal, and lateral forces that commonly occur on track.
Insulating materials that can replace the epoxy used in bonded insulated joints are researched. The electrical insulation properties and mechanical strength of different materials are examined to determine the suitability of different materials for use in insulated joint. The most promising materials for use are determined to be fiber reinforced polymers and ceramics. Insulated joint designs are developed to accentuate the strengths of these two materials. The Insulating Metal Composite (IMC) insulated joint design that uses ceramics is determined to be the most promising of the new designs and is pursued through prototype fabrication.
This particular joint design is analyzed structurally using both closed form analysis and FEA analysis using the software package ABAQUS. Electrical analysis using PSPICE is carried out on the joint. Prototypes of several design iterations of the insulating metal composites are built and tested. A proof of concept static bending test of the insulating metal composites used to build the IMC insulated joint is performed using a Tinius Olsen compressive tester. A rolling-wheel load test is performed on a prototype IMC component installed in rail. Finally, a prototype of a complete IMC insulated joint is fabricated and installed on the FAST test track at TTCI facility in Pueblo, Colorado for field evaluation. Electrical testing using a megohmmeter is performed on a complete prototype joint.
Structural analysis shows that the components used to construct the IMC insulated joint can withstand the vertical and longitudinal loads applied to them. Electrical analysis shows that the joint can provide adequate electrical insulation and provides the required dielectric strength in the AREMA Manual for Railway Engineering. The proof of concept test shows that an IMC component can withstand 100 kips of static load without damage. The rolling-wheel load test shows that the ceramic in the IMC components can withstand a large shock load and that the rail used in the IMC insulated joints can survive repeated and shock loads. The testing of the prototype joint on the FAST track, which is ongoing at this time has shown that the new joint concept is fully capable of providing adequate electrical insulation and mechanical strength throughout the expected life of IJs.Master of Science
49
Starikov, Roman. "Quasi-static and fatigue behaviour of composite bolted joints". Doctoral thesis, Stockholm, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3163.
Testo completo
50
Bahar, Mohammadreza. "The relationship between dynamic knee joint load and matrix metalloproteinases in people with and without knee osteoarthritis". Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44627.
Testo completoAbstract (sommario):
Introduction: Knee osteoarthritis (OA) is a destructive joint disease resulting from a number of factors including excessive and repetitive loading of the joints. Even though OA symptoms begin mostly in midlife, the degenerative changes of articular cartilage take place a long time before the onset, so it is important to track osteoarthritic changes at earlier phases. Radiology imaging is widely used for this purpose; however, radiology does not show minute changes that occur before onset of OA symptoms. Due to such limitations, the investigation of molecular changes is growing in today’s research. Matrix metalloproteinases (MMPs) are degenerative enzymes of connective tissue and their quantities are thought to be related to OA changes. Our goal was to investigate how MMP variance is explained by OA–related factors, mainly dynamic knee joint loading. Methods: A cross-sectional design was used to collect data on the intraarticular knee joint load, reflected by knee adduction moment (KAM), as well as serum samples in 28 participants of which half had mild to severe OA and the other half were OA-free. Laboratory-based motion analysis was used to compute the KAM, while MMP levels (MMPs- 1, 3, 13) were measured using ELISA. Multiple-regression analysis was used to investigate the explanatory role of KAM, and potential confounders like age, and OA severity in explaining MMP variance. Results: KAM impulse predicted significant variance in MMP-3 levels (R²=0.197, p=0.018). After controlling for the effect of age and severity, the explanatory role of KAM impulse was decreased (R²=0.157), still remaining statistically significant (p=0.036). The explained variance of MMP-1, 13 did not reveal statistical significance from explanatory variables. Conclusion: This research provides evidence of a positive relationship between MMP- 3 and intraarticular knee joint load, quantified by the KAM. The relationship remained significant after controlling for age and OA severity. Our findings support the notion that MMP-3 may be a candidate for OA investigations. Since MMP levels are influenced by a number of factors, it seems logical to consider the levels of other biomarkers along with them.