The present work is concerned with the development of finite element techniques for nonlinear transient dynamic analysis of reinforced concrete plates and shells. Computational models have been developed and coded, which are applied to various engineering problems under static and dynamic loading conditions. The first part of the thesis deals with some aspects of linear-elastic, geometric and material nonlinear finite element formulations of general thin and thick shell analysis under static or quasistatic loading. A generalized displacement method is proposed to overcome the 'shear locking' problem for the degenerated thick shell element when used in the context of thin shell structures. The basic concept and mathematical formulation of the generalized displacement method are detailed and its application is illustrated by numerical examples. The method is also extended to the geometrically nonlinear analysis of thin shells based on both Updated and Total Lagrangian formulation. An elasto-viscoplastic analysis of anisotropic plates and shells is developed by means of the finite element displacement method. A discrete layered approach is adopted to represent different material properties and gradual plastification through the thickness. Viscoplastic yielding is based on the Huber-Mixes criterion extended by Hill for anisotropic material and special consideration is given to the evaluation of the viscoplastic strain increment for anisotropic situations. The second part of this thesis is concerned with nonlinear dynamic transient analysis of reinforced concrete shell structures. Direct integration methods are reviewed and discussed. In particular, the general single step explicit, implicit and implicit-explicit algorithms with predictor - corrector forms are presented and corresponding stability conditions are deduced by invoking the energy method. The modelling of reinforced concrete behaviour in shell structures under fast loading conditions is considered. Both a strain rate sensitive elasto-viscoplastic model and a strain rate sensitive elasto-plastic model are presented for describing concrete nonlinearities due to multiaxial compressive or tensile yielding under dynamic loads. The models are used in conjuction with a tensile crack monitoring algorithm to trace concrete crack opening and closing. Various reinforced concrete plates and shells are analyzed and reported in detail, with the results obtained being compared with those from other sources.

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In this thesis, two-dimensional floating pier consists of single rectangular impermeable pontoon and rigid beam is studied. The purpose of this study is to present a theoretical solution for linearlized problem of incident waves acting on a floating pier with pile-restrained. All boundary conditions are linearlized in the problem which is separated into a scattering problem and radiation problem with unit motion amplitude. The method of separation of variables is used to solve for velocity potentials. For the radiation problem with unit heave and rotate amplitude, the boundary value problem with nonhomogeneous boundary condition beneath the structure is solved by using a solution procedure proposed by Lee(1995). By calculating wave force from velocity potential, and equations of motion of the floating structure, an analytic solution for the problem is developed. At last, using finite element method to calculate the dynamic analysis on the pile acting by the pontoon and incident waves.

The purpose of this study is to analyze the stress effect of the shaft, the head speed of the golf club, and the reaction force of the arm as well as the wrist under the process of the down swing. By using two softwares, the researcher conducted the study. First, I-DEAS software was used to model the club head with shaft. Next, Dyna3D software was used to analyze the swinging condition. After that the golf club and ball were placed in the three dimensional space and analyzed the dynamic behavior with the field of gravity. In order to simulate the action of swing of the golf club, the driving moment was input to the arm and the wrist. Through changing the thickness of the shaft, three different flexibility and weight of the shaft was specified. Later on, the researcher discussed the swing effect of differently flexible shaft and weight of the shaft. From the result of analysis, stiff shaft resulted in stable swing but lower head speed under the same driving moment. By contrast, the soft shaft generated higher head speed and dynamic loft angle but it resulted in less stable club head traveling path. Besides, the stiff shaft generated higher resultant force and moment to the arm and the wrist under the same driving moment. It is believed that this study will provide some reliable computer simulation data for the reference in golf sport.

This thesis introduces a versatile finite element package, which is tailored for the static and dynamic analysis of radial tyres. A new axisymmetric solid-of-revolution element which takes into consideration, large deformation, the influence of composite orthotropic material and the viscoelasticity and the nonlinearity of the material properties, has been developed for a general loaded tyre. The finite element package has been verified by comparing its results with available analytical, numerical and experimental results. A full static and dynamic investigation has been carried out for a commercial tyre 175 HR 14 and results obtained by using the package have been compared with available experimental results developed by DUNLOP or carried out at Cranfieid. The package has proved to be reliable, flexible, efficient, economic and accurate. The numerical instability problems which are prevalent in this type of analysis have been overcome by the derivation of a developed Newton-Raphson iterative scheme.

This research focuses on improvements and application of 1D finite elements for nonlinear dynamic analysis of reinforced concrete frames under extreme loadings. The concept of force interpolation is adopted for the element formulation and a solution scheme developed based on a total secant stiffness approach that provides good convergence characteristics. The geometrical nonlinearities including 2nd order P-Delta effects as well as catenary action are considered in the element formulation. It is shown that geometrical nonlinearities may have a significant effect on member (structure) response within extreme loading scenarios. In the analysis of structures subjected to extreme loadings, accurately modelling of the post peak response is vital and, in this respect, the objectivity of the solution with softening must be maintained. The softening of concrete under compression is taken into account, and the objectivity preserved, by adopting a nonlocal damage model for the compressive concrete. The capability of nonlocal flexibility-based formulation for capturing the post-peak response of reinforced concrete beam-columns is demonstrated by numerical examples. The 1D frame element model is extended for the modelling of 3D framed structures using a simplified torque-twist model that is developed to take account of interaction between normal and tangential forces at the section level. This simplified model can capture the variation of element torsional stiffness due to presence of axial force, bending moment and shear and is efficient and is shown to provide a reasonable degree of accuracy for the analysis of 3D reinforced concrete frames. The formulations and solution algorithms developed are tested for static and dynamic analysis of reinforced concrete framed structures with examples on impact analysis of beams, dynamic analysis of frames and progressive collapse assessment of frames taken from the literature. The verification shows that the formulation is very efficient and is capable of modelling of large scale framed structures, under extreme loads, quickly and with accuracy.

For automotive plastic parts there is a clear demand on an increased quality of the FE models. This demand is related to the increased use of simulations, both due to a reduced number of prototypes and an increased number of load cases. There have been studies showing a change of dynamic properties in injection molded components. The conclusion from these studies are that the change depends on residual stresses built in during the injection process. This study use simple models to try to get a working method and from the results find out the basic relations between residual stresses and dynamic properties. A method was developed and the results showed that the residuals had a major impact on the dynamic properties. Continuation on this work would be to use more complex models, to try to mimic results from reference studies and tests.

This research focuses on improvements and application of 1D finite elements for nonlinear dynamic analysis of reinforced concrete frames under extreme loadings. The concept of force interpolation is adopted for the element formulation and a solution scheme developed based on a total secant stiffness approach that provides good convergence characteristics. The geometrical nonlinearities including 2nd order P-Delta effects as well as catenary action are considered in the element formulation. It is shown that geometrical nonlinearities may have a significant effect on member (structure) response within extreme loading scenarios. In the analysis of structures subjected to extreme loadings, accurately modelling of the post peak response is vital and, in this respect, the objectivity of the solution with softening must be maintained. The softening of concrete under compression is taken into account, and the objectivity preserved, by adopting a nonlocal damage model for the compressive concrete. The capability of nonlocal flexibility-based formulation for capturing the post-peak response of reinforced concrete beam-columns is demonstrated by numerical examples. The 1D frame element model is extended for the modelling of 3D framed structures using a simplified torque-twist model that is developed to take account of interaction between normal and tangential forces at the section level. This simplified model can capture the variation of element torsional stiffness due to presence of axial force, bending moment and shear and is efficient and is shown to provide a reasonable degree of accuracy for the analysis of 3D reinforced concrete frames. The formulations and solution algorithms developed are tested for static and dynamic analysis of reinforced concrete framed structures with examples on impact analysis of beams, dynamic analysis of frames and progressive collapse assessment of frames taken from the literature. The verification shows that the formulation is very efficient and is capable of modelling of large scale framed structures, under extreme loads, quickly and with accuracy.

This thesis deals with multibody dynamic simulation of mechanical systems in the product development process. The approach is to make the process of multibody dynamics simulation more efficient by structuring of the simulation, simulation models and their usage. Previous work has concentrated on developing faster calculation methods and more specialised simulation software. Efforts have been made to clarify how computer tools and multibody dynamic analysis methods are used in product development in industry today. Insight into the knowledge domains of product development and multibody dynamics is given together with an introduction to the area of distributed simulation, modularisation techniques and nonlinear analysis. The mentioned domains have traditionally been separated but the introduction of concurrent engineering and faster computers puts new demands on the need for integration of computer support and analysis in the development process. The performed work is to be seen as cross-functional work in order to bring different domains together for the sake of a better total product development. The applications areas used in the work are all within vehicle system dynamics. A proposal for performing the multibody dynamics methodology in a distributed and modular way in the product development process is given based on the performed work together with a prototype implementation.

This thesis presents the results of a study of the effect of variations of systemic parameters on the structural response of single degree of freedom systems subjected to Incremental Dynamic Analysis. The systemic parameters are mass, stiffness, damping, yield strength and geometric stiffness. Each of these parameters was varied one at a time while the other values were kept constant. For each variation of parameters a set of single-record IDA curves was obtained. Five to six ground motions were used for this study to generate the single-record IDA curves. These ground motions were scaled prior to their application on the structure. The scaling factor was based on the spectral acceleration at the fundamental frequency of the structure at 5% of critical damping. The scale factor is affected if the system parameters are changed. An important issue for this study was whether to persist with scaling corresponding to the median value from the range of the values of the parameter or to update the scaling according to the system. Based on some tests using both methods, the median scaling approach was found to be more suitable. The IDA curves for variation of parameters were then investigated to identify any trends that may help in qualitatively predicting the response of a system relative to another system. The response was measured by the peak displacement and the maximum base shear of the system. A clear trend was identified when the damping or the yield strength was varied. However, no definite trend was observed when the material stiffness or the geometric stiffness of the system was varied. / Master of Science