Safety is an important aspect when designing bridges and roads. One aspect among others to consider is the road restraint systems. The focus of this study was centered to safety barriers which are the vehicle parapets/guardrails. The parapet must meet certain requirements specified in European Standard in order to obtain a CE-marking, indicating the acceptance of use. Full-scale test must be performed for a proposed parapet to evaluate the performance. Often several full-scale tests are performed in order to achieve CE-marking, making it an expensive process. The primary objective of this master thesis was to investigate if Abaqus/Explicit could be used as the finite element software for simulation of crashes. Secondary objective was to investigate how well a performed full-scale crash could be simulated in Abaqus/Explicit. A full-scale test was conducted and the parapet installation and vehicle used was modeled. Same conditions as in the full-scale were used in the simulation. The results indicated that it is possible to simulate the full-scale crash using Abaqus/Explicit. However, the behavior of the full-scale test was not completely captured. The maximum dynamic and permanent horizontal deflection of the tabular thrie beam in the full-scale test was 582 mm and 515 mm, corresponding value from the simulation was 703 mm and 643 mm. The conclusion from the results is that Abaqus/Explicit is a suitable finite element software for simulating crashes. The differences between the full-scale test and the simulations in this master thesis were due to the simplifications and assumptions used when modeling the parapet, bridge deck and the vehicle. The overall global behavior of the full-scale test was not captured, however the simulation results were not far from the full-scale test even though rough simplifications and assumptions were used in the modeling. We believe that with more care to details in modeling, it should be possible to have better convergence between simulation and the full-scale test.

Sheet trimming is an important forming operation in stamping industry. However, trimming of automotive magnesium sheet materials is not well understood. The objective of present study was to investigate the trimming behavior of AZ31 and ZEK100 automotive magnesium sheet materials using a laboratory-based experimental set-up and complementary finite element (FE) simulations of the lab-based experiments. The effects of the trimming process parameters that included tool setup configuration, punch speed, clearance, sheet thickness and sheet orientation (rolling and transverse directions) on the quality of trimmed edge were analyzed. Experimental results indicated that the trimmed edge quality depended strongly on the trimming conditions. The optimal trimming parameters for AZ31 and ZEK100 sheets were experimentally obtained. Interrupted trimming experiments were conducted to examine crack initiation and development, the mechanism of fracture, and the generation of the fracture profile of the trimmed edges. The R-value as a measure of material anisotropy and fracture strain of both materials were measured using uniaxial tension and plane strain tests and incorporated in the FE model. General purpose Finite Element software ABAQUS/Explicit was employed to simulate the trimming process where five different fracture criteria and element deletion method were used to predict profile of trimmed edge and the fracture initiation and development during the trimming process. Good general agreement was observed between experiments and FE simulations. However, some discrepancies were also observed. These are presented and discussed in the thesis. / Thesis / Master of Applied Science (MASc)

Le travail principal de cette thèse consiste à proposer une nouvelle procédure d'identification inverse appliquée aux situations de mise en forme et d'usinage des métaux, qui peut fournir un ensemble de paramètres appropriés pour toute loi constitutive elastoplastique suivant le modèle de plasticité de type J_{2} avec écrouissage isotrope, en évaluant la corrélation entre les réponses expérimentales et numériques. En premier lieu, un programme d'identification a été développé, en combinant l'algorithme de Levenberg-Marquardt et des méthodes de traitement de données pour identifier les paramètres constitutifs. En termes d'expérimentation, des essais de compression et de traction dynamiques ont été effectués. La forme finale déformée des spécimens, qui repose sur une analyse post-mortem, a été choisie comme quantité d'observation. Comme pour la simulation numérique, des modèles numériques de ces mêmes procédures expérimentales ont été construits en utilisant le code éléments finis Abaqus/Explicit afin de fournir des réponses numériques. Un algorithme numérique a été proposé pour l'implémentation de lois constitutives elastoplastiques définies par l'utilisateur dans Abaqus/Explicit. / The main concern of this thesis is to propose a new inverse identification procedure applied to metal forming and machining situations, which can provide an appropriate parameters set for any elastoplastic constitutive law following J_{2} plasticity and isotropic hardening, by evaluating the correlation between the experimental and numerical responses. Firstly the identification program has been developed, which combines the Levenberg-Marquardt algorithm and the Data processing methods to optimize the constitutive parameters. In terms of experimentation, dynamic compression and tensile tests have been conducted. The final deformed shape of specimens, which relies on a post-mortem analysis, has been selected as the observation quantity. As for the numerical simulation, the numerical models of the same experimental procedure have been built with the finite element software Abaqus/Explicit in order to provide numerical responses. A numerical algorithm has been proposed for the implementation of user defined elastoplastic constitutive laws in Abaqus/Explicit.

The main concern of this thesis is to propose a new inverse identification procedure applied to metal forming and machining situations, which can provide an appropriate parameters set for any elastoplastic constitutive law following J_{2} plasticity and isotropic hardening, by evaluating the correlation between the experimental and numerical responses. Firstly the identification program has been developed, which combines the Levenberg-Marquardt algorithm and the Data processing methods to optimize the constitutive parameters. In terms of experimentation, dynamic compression and tensile tests have been conducted. The final deformed shape of specimens, which relies on a post-mortem analysis, has been selected as the observation quantity. As for the numerical simulation, the numerical models of the same experimental procedure have been built with the finite element software Abaqus/Explicit in order to provide numerical responses. A numerical algorithm has been proposed for the implementation of user defined elastoplastic constitutive laws in Abaqus/Explicit.

A finite element model of fibre metal laminate (FML) fuselage was developed in order to evaluate its impact response under survivable crash event. To create a reliable crash finite element (FE) model of FML fuselage, a ‘building block approach’ is adapted. It involves a series of validation and verification tasks in order to establish reliable material and damage models, verified impact model with structural instability and large displacement and verified individual fuselage structure under crash event. This novel development methodology successfully produced an FE model to simulate crash of both aluminium alloy and FML fuselage under survivable crash event using ABAQUS/Explicit. On the other hand, this allows the author to have privilege to evaluate crashworthiness of fuselage that implements FML fuselage skin for the whole fuselage section for the first time in aircraft research field and industry. The FE models consist of a two station fuselage section with one meter longitudinal length which is based on commercial Boeing 737 aircraft. For FML fuselage, the classical aluminium alloy skin was replaced by GLARE grade 5-2/1. The impact response of both fuselages was compared to each other and the results were discussed in terms of energy dissipation, crushing distance, failure modes, failure mechanisms and acceleration response at floor-level. Overall, it was observed that FML fuselage responded similarly to aluminium alloy fuselage with some minor differences which conclusively gives great confidence to aircraft designer to use FML as fuselage skin for the whole fuselage section. In terms of crushing distance, FML fuselage skin contributed to the failure mechanisms of the fuselage section that lead to higher crushing distance than in aluminium alloy fuselage. The existence of various failure modes within FML caused slight differences from the aluminium fuselage in terms of deformation process and energy dissipation. These complex failure modes could potentially be manipulated to produce future aircraft structure with better crashworthiness performance.

Understanding the true behaviour of impacted structures is the only way to assess their robustness under exceptional events such as vehicle collision. The primary objective of this master’s thesis was to perform a finite element parametric investigation on the influence that some parameters have in steel buildings subjected to vehicle impacts. The parameters chosen for the study, involved uncertainties in the material definition and in the load configuration of the bolts used in the impacted column end-connections. By using the Abaqus software, a finite element model of the structure has been created. The five storey steel building considered has been modelled in a simplified manner with the exception of the impacted area which, instead, has been defined in a more detailed fashion. During the simulations, different preload conditions have been used, comparing cases with and without the preload force. Regardless its variation, it has not been observed any increase in the structural resistance. On the other hand, the simulation provided interesting results for what concerns the material variations in the bolts. Although the changes have been small in magnitude, the effect on the structural response during the impact was remarkable. For all the cases considered, an increase of the material ductility, achieved by increasing the ultimate strain at failure, entailed higher resistance of the connections. Various failure modes have been observed when the material properties have been changed. Having clarified the influence of the assumptions made, the results provided helpful information in sight of future studies. Although the model still needs to be validated, the research clarified which of the parameters investigated are to be collected with more attention. Keywords: Vehicle collision, steel building, FE model, Abaqus/Explicit, parametric investigation, bolt preload, bolt material.

O ensaio SPT (Standard Penetration Test), é o ensaio de campo geotécnico mais usado no Brasil e grande parte do mundo. A ampla utilização deste ensaio no âmbito da engenharia geotécnica deve-se à sua simplicidade, baixo custo, grande experiência prática e facilidade de aplicação dos seus resultados. Os principais objetivos do ensaio são a determinação do índice de resistência do solo (NSPT) e amostragem. Apesar de ser muito utilizado na estimativa da capacidade de carga de fundações, o ensaio SPT tem sido questionado pelo fato de que o índice NSPT é utilizado em correlações empíricas baseadas em observações práticas, sem nenhum fundamento científico. Além do mais, seus resultados apresentam significativas dispersões. Para analisar racionalmente os resultados do ensaio e de possibilitar a comparação dos diferentes resultados de distintas equipes, é necessário conhecer as quantidades de energia envolvidas na penetração do amostrador no solo. Tais análises requerem o conhecimento da eficiência do equipamento (η) e a força de reação dinâmica do solo à cravação do amostrador (RD). Neste cenário, o presente trabalho aborda a interpretação racional dos resultados de ensaios SPT a partir de simulações numéricas realizadas com o software Abaqus/Explicit®. Esse programa fornece os deslocamentos do amostrador (Δρ), força de reação dinâmica do solo (RD), e as forças de reação nas paredes laterais externa e interna do amostrador (R1 e R2). Baseando-se nos resultados dos modelos numéricos, foi possível calcular a eficiência do equipamento, a partir da força de reação dinâmica do solo, as resistências unitárias de atrito atuantes nas paredes e a resistência unitária na ponta do amostrador. Também foi possível determinar a relação entre as resistências unitárias de atrito desenvolvidas no interior e exterior do amostrador (fator de atrito a). Os resultados obtidos foram comparados com resultados de trabalhos experimentais e valores teóricos determinados com base no Princípio de Hamilton da conservação da energia. Também foi possível simular uma prova de carga dinâmica com energia crescente no amostrador, variando a altura de queda do martelo. Isso confirmou que a resistência mobilizada do solo para certa energia aplicada pode estar bem abaixo da ruptura e apenas representar um ponto na curva de resistência mobilizada versus deslocamento. / The Standard Penetration Test (SPT) is one of the most used geotechnical tests in the world. The wide use of this test in the context of geotechnical engineering is due to its simplicity, low cost, large practical experience and its ease of application of results. The main objectives of the test are the determination of soil resistance index (NSPT) and sampling. Despite being widely used in estimating the bearing capacity of foundations, the SPT test has been questioned by the fact that the NSPT index is used in empirical correlations based on practical observations, with no scientific basis. Furthermore, its results show significant dispersions. To analyze rationally the test results and to make possible to compare different results obtained from different equipment, it is necessary to know the amounts of energy existing during the penetration of the sampler into soil. Such analyses require information about the equipment efficiency (η) and the dynamic soil reaction force during the sampler penetration (RD). In this scenario, this work addresses the rational interpretation of SPT test results from numerical simulations performed with the Abaqus/Explicit software. This program provides the sampler displacements (Δρ), the dynamic soil reaction force (RD) and the external and internal reaction forces acting on the sampler walls (R1 e R2). Based on the results of the numerical models, it was possible to calculate the efficiency of the equipment, from the dynamic soil reaction force, the unit friction resistance acting on the sampler walls and the unit resistance at the sampler tip. In addition, it was possible to estimate the relationship between the unit friction resistance acting on the internal and external walls of the sampler (friction factor a). The numerical results were compared with experimental results and theoretical values, obtained using the Hamilton\'s principle of conservation of energy. Furthermore, it was possible to simulate a dynamic load test with increasing energy applied to the sampler, by varying the height of fall of the hammer. It was obtained the confirmation that resistance mobilized for a certain level of energy applied to the sampler may be below the failure load and represent only a point on the graph curve mobilized resistance versus displacement.

O ensaio SPT (Standard Penetration Test), é o ensaio de campo geotécnico mais usado no Brasil e grande parte do mundo. A ampla utilização deste ensaio no âmbito da engenharia geotécnica deve-se à sua simplicidade, baixo custo, grande experiência prática e facilidade de aplicação dos seus resultados. Os principais objetivos do ensaio são a determinação do índice de resistência do solo (NSPT) e amostragem. Apesar de ser muito utilizado na estimativa da capacidade de carga de fundações, o ensaio SPT tem sido questionado pelo fato de que o índice NSPT é utilizado em correlações empíricas baseadas em observações práticas, sem nenhum fundamento científico. Além do mais, seus resultados apresentam significativas dispersões. Para analisar racionalmente os resultados do ensaio e de possibilitar a comparação dos diferentes resultados de distintas equipes, é necessário conhecer as quantidades de energia envolvidas na penetração do amostrador no solo. Tais análises requerem o conhecimento da eficiência do equipamento (η) e a força de reação dinâmica do solo à cravação do amostrador (RD). Neste cenário, o presente trabalho aborda a interpretação racional dos resultados de ensaios SPT a partir de simulações numéricas realizadas com o software Abaqus/Explicit®. Esse programa fornece os deslocamentos do amostrador (Δρ), força de reação dinâmica do solo (RD), e as forças de reação nas paredes laterais externa e interna do amostrador (R1 e R2). Baseando-se nos resultados dos modelos numéricos, foi possível calcular a eficiência do equipamento, a partir da força de reação dinâmica do solo, as resistências unitárias de atrito atuantes nas paredes e a resistência unitária na ponta do amostrador. Também foi possível determinar a relação entre as resistências unitárias de atrito desenvolvidas no interior e exterior do amostrador (fator de atrito a). Os resultados obtidos foram comparados com resultados de trabalhos experimentais e valores teóricos determinados com base no Princípio de Hamilton da conservação da energia. Também foi possível simular uma prova de carga dinâmica com energia crescente no amostrador, variando a altura de queda do martelo. Isso confirmou que a resistência mobilizada do solo para certa energia aplicada pode estar bem abaixo da ruptura e apenas representar um ponto na curva de resistência mobilizada versus deslocamento. / The Standard Penetration Test (SPT) is one of the most used geotechnical tests in the world. The wide use of this test in the context of geotechnical engineering is due to its simplicity, low cost, large practical experience and its ease of application of results. The main objectives of the test are the determination of soil resistance index (NSPT) and sampling. Despite being widely used in estimating the bearing capacity of foundations, the SPT test has been questioned by the fact that the NSPT index is used in empirical correlations based on practical observations, with no scientific basis. Furthermore, its results show significant dispersions. To analyze rationally the test results and to make possible to compare different results obtained from different equipment, it is necessary to know the amounts of energy existing during the penetration of the sampler into soil. Such analyses require information about the equipment efficiency (η) and the dynamic soil reaction force during the sampler penetration (RD). In this scenario, this work addresses the rational interpretation of SPT test results from numerical simulations performed with the Abaqus/Explicit software. This program provides the sampler displacements (Δρ), the dynamic soil reaction force (RD) and the external and internal reaction forces acting on the sampler walls (R1 e R2). Based on the results of the numerical models, it was possible to calculate the efficiency of the equipment, from the dynamic soil reaction force, the unit friction resistance acting on the sampler walls and the unit resistance at the sampler tip. In addition, it was possible to estimate the relationship between the unit friction resistance acting on the internal and external walls of the sampler (friction factor a). The numerical results were compared with experimental results and theoretical values, obtained using the Hamilton\'s principle of conservation of energy. Furthermore, it was possible to simulate a dynamic load test with increasing energy applied to the sampler, by varying the height of fall of the hammer. It was obtained the confirmation that resistance mobilized for a certain level of energy applied to the sampler may be below the failure load and represent only a point on the graph curve mobilized resistance versus displacement.

A three dimensional nonlinear finite element model has been developed to study the behaviour of composite beams with profiled sheeting oriented perpendicular to its axis. The analysis of the push test was carried out using ABAQUS/Explicit with slow load application to ensure a quasi-static solution. Both material and geometric nonlinearities were taken into account. Elastic¿plastic material models were used for all steel components and the Concrete Damaged Plasticity model was used for the concrete slab. The post-failure behaviour of the push test was accurately predicted, which is crucial for realistic determination of shear capacity, slip and failure mode. The results obtained from finite element analysis were verified against the experimental push tests conducted in this research and also from other studies. After validation, the model was used to carry out an extensive parametric study to investigate the effect of transverse spacing in push tests with double studs placed in favourable and staggered positions with various concrete strengths. The results were also compared with the capacity of a single shear stud. It was found that shear connector resistance of pairs of shear connectors placed in favourable position was 94% of the strength of a single shear stud on average, when the transverse spacing between studs was 200 mm or more. For the same spacing, the resistance of staggered pairs of studs was only 86% of the strength of a single stud. The strength of double shear studs in favourable position was higher than that of the staggered pairs of shear connectors.

This paper presents a numerical investigation into the behaviour of headed shear stud in composite beams with profiled metal decking. A three-dimensional finite element model was developed using general purpose finite element program ABAQUS to study the behaviour of through-deck welded shear stud in the composite slabs with trapezoidal deck ribs oriented perpendicular to the beam. Both static and dynamic procedures were investigated using Drucker Prager model and Concrete Damaged Plasticity model respectively. In the dynamic procedure using ABAQUS/Explicit, the push test specimens were loaded slowly to eliminate significant inertia effects to obtain a static solution. The capacity of shear connector, load-slip behaviour and failure modes were predicted and validated against experimental results. The delamination of the profiled decking from concrete slab was captured in the numerical analysis which was observed in the experiments. ABAQUS/Explicit was found to be particularly suitable for modelling post-failure behaviour and the contact interaction between profiled decking and concrete slabs. It is concluded that this model represents the true behaviour of the headed shear stud in composite beams with profiled decking in terms of the shear connection capacity, load-slip behaviour and failure modes.