Supported stope mining is one of the most common types of mining in the modern day gold mining industry. The excavated regions, where ore is extracted, are supported with a combination of roof-bolting, timber packs, backfill, timber props and mechanical prop technologies. In order to install a support system that will be able to absorb the energy released by the elastic movement of the surrounding rock mass and support the unstable hanging wall, it is necessary for the rock engineer to know how the individual types of support will react to different load conditions in order to design a safe support system. Current support systems are developed using knowledge from past experience and trial and error processes. These are expensive and time consuming methods that can possibly be improved and made more cost effective by using modern design techniques. A study was conducted to determine the feasibility of the application of Finite Element Modelling (FEM) to the deformation of a modern support unit under specified quasi-static and dynamic stope load conditions with the view to assist in the prediction of the operational performance of support units that cannot be experimentally tested due to a lack of test equipment, capabilities and facilities. The study was extended by investigating the theoretical possibility of buckling due to an impact load on the prop and the performance of the prop. To achieve this, a simulation was carried out using ANSYS™ transient structural software to determine whether it is possible to simulate the performance curve of a prop. Computerised methods were used to determine the possibility of failure due to buckling and the implications of buckling, if it occurs, on the performance of a specific support prop design. In summary this study proved that it is possible to simulate the performance curve of a friction prop design in order to compare the result obtained with the required performance, provided that the correct friction coefficients between prop mating surfaces are known. It also presents a methodology to investigate the theoretical effect of high velocity impact load on the buckling potential of a friction prop design and slender columns in general, which is highly applicable to these types of support. The methodologies used in this study can be applied to different designs of friction props, and possibly reduce the development costs and implementation time of these types of support units. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

Supported stope mining is one of the most common types of mining in the modern day gold mining industry. The excavated regions, where ore is extracted, are supported with a combination of roof-bolting, timber packs, backfill, timber props and mechanical prop technologies. In order to install a support system that will be able to absorb the energy released by the elastic movement of the surrounding rock mass and support the unstable hanging wall, it is necessary for the rock engineer to know how the individual types of support will react to different load conditions in order to design a safe support system. Current support systems are developed using knowledge from past experience and trial and error processes. These are expensive and time consuming methods that can possibly be improved and made more cost effective by using modern design techniques. A study was conducted to determine the feasibility of the application of Finite Element Modelling (FEM) to the deformation of a modern support unit under specified quasi-static and dynamic stope load conditions with the view to assist in the prediction of the operational performance of support units that cannot be experimentally tested due to a lack of test equipment, capabilities and facilities. The study was extended by investigating the theoretical possibility of buckling due to an impact load on the prop and the performance of the prop. To achieve this, a simulation was carried out using ANSYS™ transient structural software to determine whether it is possible to simulate the performance curve of a prop. Computerised methods were used to determine the possibility of failure due to buckling and the implications of buckling, if it occurs, on the performance of a specific support prop design. In summary this study proved that it is possible to simulate the performance curve of a friction prop design in order to compare the result obtained with the required performance, provided that the correct friction coefficients between prop mating surfaces are known. It also presents a methodology to investigate the theoretical effect of high velocity impact load on the buckling potential of a friction prop design and slender columns in general, which is highly applicable to these types of support. The methodologies used in this study can be applied to different designs of friction props, and possibly reduce the development costs and implementation time of these types of support units. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

Hundreds of thousands of dollars could be lost due to failures during the fabrication of Trunnion-Hub-Girder (THG) assemblies of bascule bridges. Two different procedures are currently utilized for the THG assembly. Crack formations in the hubs of various bridges during assembly led the Florida Department of Transportation (FDOT) to commission a project to investigate why the assemblies failed. Consequently, a research contract was granted to the Mechanical Engineering department at USF in 1998 to conduct theoretical, numerical and experimental studies. It was found that the steady state stresses were well below the yield strength of the material and could not have caused failure. A parametric finite element model was designed in ANSYS to analyze the transient stresses, temperatures and critical crack lengths in the THG assembly during the two assembly procedures. The critical points and the critical stages in the assembly were identified based on the critical crack length. Furthermore, experiments with cryogenic strain gauges and thermocouples were developed to determine the stresses and temperatures at critical points of the THG assembly during the two assembly procedures. One result revealed by the studies was that large tensile hoop stresses develop in the hub at the trunnion-hub interface in AP1 when the trunnion-hub assembly is cooled for insertion into the girder. These stresses occurred at low temperatures, and resulted in low values of critical crack length. A suggestion to solve this was to study the effect of thickness of the hub and to understand its influence on critical stresses and crack lengths. In addition, American Association of State Highway and Transportation Officials (AASHTO) standards call for a hub radial thickness of 0.4 times the inner diameter while currently a thickness of 0.1 to 0.2 times the inner diameter is used. In this thesis, the geometrical dimensions are changed according to the design of experiments standards to find the sensitivity of these parameters on critical stresses and critical crack lengths during the assembly. Parameters changed are hub radial thickness to trunnion outer diameter ratio, trunnion outer diameter to trunnion bore diameter ratio and variations of the interference. The radial thickness of the hub was found to be the most influential parameter on critical stresses and critical crack lengths.

The aim of this thesis was to study the load bearing capacity of anchor plates, used for anchorage to concrete located at nuclear facilities. Two different type of anchor plates were examined, which together constitute the majority of the anchor plates used at Forsmark nuclear facility in Sweden. The first is a cast-in-place anchor plate with headed studs and the second is a post-installed anchor plate which uses sleevetype expansion anchors. Hence, anchors with both a mechanical or a frictional interlock to the concrete were examined. The main analysis tool was the finite element method, through the use of the two commercially available software packages ABAQUS and ADINA and their non-linear material models for concrete and steel. As a first step, the numerical methods were verified against experimental results from the literature. However, these only concern single anchors. The results from the verifications were then used to build the finite element models of the anchor plates. These were then subjected to different load combinations with the purpose to find the ultimate load capacity. Failure loads from the finite element analyses were then compared to the corresponding loads calculated according to the new European technical specification SIS-CEN/TS 1992-4 (2009). Most of the failure loads from the numerical analyses were higher than the loads obtained from the technical specification, although in some cases the numerical results were lower than the technical specification value. However, many conservative assumptions regarding the finite element models were made, hence there might still be an overcapacity present. All analyses that underestimate the failure load were limited to large and slender anchor plates, which exhibit an extensive bending of the steel plate. The bending of the steel plate induce shear forces on the anchors, which leads to a lower tensile capacity. In design codes, which assume rigid steel plates, this phenomenon is neglected. The failure loads from all different load combinations analysed were then used to develop failure envelopes as a demonstration of a useful technique, which can be utilised in the design process of complex load cases.

As vigas mistas aço-concreto têm sido bastante utilizadas na engenharia civil, tanto no Brasil como no contexto mundial. O comportamento adequado deste elemento estrutural faz-se pela interação entre ambos os materiais, a qual é garantida por conectores de cisalhamento. O presente trabalho apresenta uma visão geral do comportamento das vigas mistas aço-concreto, e, principalmente o estudo do comportamento estrutural de conectores de cisalhamento. Para tanto, faz-se uma simulação numérica dos conectores tipo pino com cabeça (stud) e perfil “U" formado a frio, por meio de uma modelagem do ensaio experimental tipo “Push-out", cujos resultados são confrontados com valores experimentais obtidos de ensaios realizados em laboratório. Para a simulação numérica utiliza-se um código de cálculo com base nos Método dos Elementos Finitos (MEF), cujas ferramentas disponibilizadas permitem análises dos modelos em regime de não-linearidade física e geométrica. Os modelos numéricos apresentam como variáveis de interesse o número de conectores na laje de concreto, a quantidade de armadura inserida no concreto, o diâmetro do conector tipo pino com cabeça (stud), a resistência do concreto, a espessura e posição de soldagem do conector tipo perfil “U" formado a frio. A variação desses parâmetros tem como finalidade a determinação da resistência última e da relação força-deslocamento dos conectores, bem como avaliar a concentração de tensão e deformação nas partes constituintes dos modelos / Composite steel-concrete beams have been used in civil engineering in Brazil as well other countries. A realistic determination of the behaviour of this structural element is estimated by considering the interaction between the two materials, which is safeguarded by providing shear connectors. The present research presents a general view of the behaviour of steel-concrete composite beams, and primarily the study of the behaviour of shear connectors. To meet this ends, a numerical analysis of stud bolt and cold formed U-channel under push-out test geometry was carried out and the results compared to experimental test results. The numerical analysis utilises a Finite Element Method (FEM) code that permits the analysis under non-linear material and geometric regimes. The main numerical variables in the study were the number of connectors used in the concrete plate, the quantity steel reinforcement, the diameter of stub bolt connector, concrete strength, the thickness and position of welding of the cold-formed U-channel. The main objective of varying these parameters was to determine the ultimate strength and the load-slip behaviour of the connectors as well as evaluate the stress and strain concentrations in certain parts that constitute the models

As vigas mistas aço-concreto têm sido bastante utilizadas na engenharia civil, tanto no Brasil como no contexto mundial. O comportamento adequado deste elemento estrutural faz-se pela interação entre ambos os materiais, a qual é garantida por conectores de cisalhamento. O presente trabalho apresenta uma visão geral do comportamento das vigas mistas aço-concreto, e, principalmente o estudo do comportamento estrutural de conectores de cisalhamento. Para tanto, faz-se uma simulação numérica dos conectores tipo pino com cabeça (stud) e perfil “U” formado a frio, por meio de uma modelagem do ensaio experimental tipo “Push-out”, cujos resultados são confrontados com valores experimentais obtidos de ensaios realizados em laboratório. Para a simulação numérica utiliza-se um código de cálculo com base nos Método dos Elementos Finitos (MEF), cujas ferramentas disponibilizadas permitem análises dos modelos em regime de não-linearidade física e geométrica. Os modelos numéricos apresentam como variáveis de interesse o número de conectores na laje de concreto, a quantidade de armadura inserida no concreto, o diâmetro do conector tipo pino com cabeça (stud), a resistência do concreto, a espessura e posição de soldagem do conector tipo perfil “U” formado a frio. A variação desses parâmetros tem como finalidade a determinação da resistência última e da relação força-deslocamento dos conectores, bem como avaliar a concentração de tensão e deformação nas partes constituintes dos modelos / Composite steel-concrete beams have been used in civil engineering in Brazil as well other countries. A realistic determination of the behaviour of this structural element is estimated by considering the interaction between the two materials, which is safeguarded by providing shear connectors. The present research presents a general view of the behaviour of steel-concrete composite beams, and primarily the study of the behaviour of shear connectors. To meet this ends, a numerical analysis of stud bolt and cold formed U-channel under push-out test geometry was carried out and the results compared to experimental test results. The numerical analysis utilises a Finite Element Method (FEM) code that permits the analysis under non-linear material and geometric regimes. The main numerical variables in the study were the number of connectors used in the concrete plate, the quantity steel reinforcement, the diameter of stub bolt connector, concrete strength, the thickness and position of welding of the cold-formed U-channel. The main objective of varying these parameters was to determine the ultimate strength and the load-slip behaviour of the connectors as well as evaluate the stress and strain concentrations in certain parts that constitute the models

Master thesis is based on a doctor thesis dealing with the behavior of reinforced concrete elements stressed shear by the author Ing. Stanislav Martinec, Ph.D. Author master thesis has the task create a spatial finally element model loading testing construction and researched the wall element. Defined finally elements model is mainly to provide proper interaction test device steel frame with the test wall element. Need for sufficiently detailed numerical analysis is necessary to define the non-linear concrete material model, that is researched element, using the extensions multiPlas for calculation software Ansys. The key output parameters, for comparison with the results of load tests, are total bevel and maximum level of applied force on the wall element. The goal is assess the effect of a steel frame, contained in finally element model, to output parameters for by non-linear numerical analysis.

This master’s thesis is dealing with analysis of fluid flow pulse in a flexible tube representing e.g. an artery in a human body. In ANSYS program, 3D simulations were performed, and these are so-called interrelated FSI analysis. In Maple software, 1D simulations of fluid flow in the tube were performed for various thin-walled and thick-walled variants. The aim is using these programs to determine the flow rates and pressures in the tube, its wall deformation and stress. Therefore, the theoretical part deals mainly with basic equations of flow dynamics, linear and nonlinear models and rotationally symmetric vessels. In the computational part are described individual procedures in the mentioned programs.

The master thesis is focused on the simulation of the toroid coils in Ansoft Maxwell 3D software, which uses finite element method for electromagnetic field simulation. Firstly the process creation of the geometric model toroid coil with seventy-five threaded is presented. It is necessary to debug this model and prepare it for the mesh generation. Physical properties are assign to this model and it gives rise to the physical model. We will set boundaries, excitation current, core material, winding material and the parameters for the mesh generations. New material Kashke K4000 will be created in the materials library and subsequently we will define its BH curve on the basis of datasheet. Analysis is made in two modes. Direct currents (7,5A; 10A; 15A; 20A; 25A) and (non)linear materials are used in magnetostatic solution. Toroid coil is excited by current pulse in transient solution. In Ansoft Maxwell Circuit editor a source which generates current pulse will be created. This excitation will be assigned to the toroid coil as an extern source through a terminal. Core material is linear in the case of transient analysis, because Ansoft Maxwell 3D doesn´t allow to use nonlinear material in this solution. Settings are different in transient and in magnetostatic analysis. End time and time step are entered to solve this task in transient analysis. Time points are entered too. Flux density and electromagnetic field strength are calculated in these time points and later it will be possible to view the results. Calculated fields are shown as the pictures in this thesis. The procedure how to use a field calculator in the postprocessing is given as well. The achievements are summarized in the conclusion.