Indiana University-Purdue University Indianapolis (IUPUI) / Additively manufactured (AM) metals have been increasingly fabricated for structural applications. However, a major hurdle preventing their extensive application is lack of understanding of their mechanical properties. To address this issue, the objective of this research is to develop a computational model to simulate the creep behavior of nickel alloy 718 manufactured using the laser powder bed fusion (L-PBF) additive manufacturing process. A finite element (FE) model with a subroutine is created for simulating the creep mechanism for 3D printed nickel alloy 718 components. A continuum damage mechanics (CDM) approach is employed by implementing a user defined subroutine formulated to accurately capture the creep mechanisms. Using a calibration code, the material constants are determined. The secondary creep and damage constants are derived using the parameter fitting on the experimental data found in literature. The developed FE model is capable to predict the creep deformation, damage evolution, and creep-rupture life. Creep damage and rupture is simulated as defined by the CDM theory. The predicted results from the CDM model compare well with experimental data, which are collected from literature for L-PBF manufactured nickel alloy 718 of creep deformation and creep rupture, at different levels of temperature and stress. Using the multi-regime Liu-Murakami (L-M) and Kachanov-Rabotnov (K-R) isotropic creep damage formulation, creep deformation and rupture tests of both the secondary and tertiary creep behaviors are modeled. A single element FE model is used to validate the model constants. The model shows good agreement with the traditionally wrought manufactured 316 stainless steel and nickel alloy 718 experimental data collected from the literature. Moreover, a full-scale axisymmetric FE model is used to simulate the creep test and the capacity of the model to predict necking, creep damage, and creep-rupture life for L-PBF manufactured nickel alloy 718. The model predictions are then compared to the experimental creep data, with satisfactory agreement. In summary, the model developed in this work can reliably predict the creep behavior for 3D printed metals under uniaxial tensile and high temperature conditions.

Tato práce řeší návrh komplexního modelu asynchronního stroje, pomocí něhož se dá stroj analyzovat. Model se skládá z dílčích modelů, které popisují asynchronní stroj z hlediska elektro-magnetického, elektrického a tepelného. Elektromagnetický model je řešen pomocí metody koneč-ných prvků v programu zvaném FEMM. Další výpočty jsou provedeny pomocí Matlabu. Tepelný model počítá s ustáleným stavem stroje v požadovaném pracovním bodě. Elektrický model je řešen pomocí náhradního schématu, ze kterého jsou odvozeny vztahy pro elektrické veličiny. Výsledný propojený model je naprogramován v Matlabu a slouží jako nástroj pro analyzování asynchronního stroje.

This thesis deals with the design of steering holder for a race car in the category Formula Student using topology optimisation and analysis of this design. The objective of this thesis is gaining knowledge about topology optimisation and application of this knowledge to the design of a replacement of the steering gearbox and its holder.

This master thesis deals with steam turbine blade attachment. Main goal is to perform strength analysis of the given geometry under static and cyclic loads by FEM and software ANSYS. Every particular model is described separately with mentioning of the problems which had to be solved. To create model of material, the tensile tests has been performed and results has been evaluate. There were planned and performed the low cycle fatigue tests to create a model of ultimate states which is used to evaluate the fatigue life of the attachment. Results of the nonlinear FEM analysis is discussed and some improvements of the geometry has been proposed to achieve better state of stress. Finally, the plan of future work has been proposed.

This masters´s thesis deals with computational modeling of transtibial lower-limb prosthesis. For assesment of loading character and geometrical configuration, the gait analysis of an amputee, including ground reaction force measurement, strain gauge analysis and motion analysis, was accomplished. Information on geometry was obtained using 3D optical scanning procedure. Material model was gathered using non-destructive mechanical testing and mimicked in a FEA software. For loading conditions the static structure analysys using FEM was accomplished. The critical poins in construction was found. Recognition of agreement about experimental and computational model was accomplished.

This master thesis deals with lower-limb prosthesis. The aim of the first part of this work is stress-strain analysis of trans-tibial prosthesis, which is understand without prosthetic socket and the foam prosthetic feet. Analysis is made using finite element method in ANSYS Workbench 12.0 software. For the purpose of setting up the computational model it is necessary to make few partial models. Model of geometry of the prosthesis is made in SolidWorks 2009. Based on the outputs of stress-strain analysis and the results evaluation, the critical component is chosen and this one is evaluated according to limite state for fatigue. The algorithm of evaluation of named component in the state of high cycle fatigue is discussed in the second part of this thesis.

This diploma thesis deals with design of uprights and wheel hubs of front wheels of Formula Student race car. Specifically race cars named Dragon 3 and Dragon 4 of TU Brno Racing team. In this thesis there will be load calculations of front wheels, choosing of bearings and uprights and wheel hub’s design. Then control of design by FEA analysis. And finally comparing of both designs and comparing with previous designs.

This master thesis deals with creation of computational model for stress - strain analysis of front car seat folding mechanism. The calculation has been done using FEM for static and dynamic load case. The results displayed the critical area of mechanism and determined the value of force when the safety of mechanism is not guaranteed and the force when the mechanism failure occurs. According to results from both load cases was made a statement that is necessary to model the dynamic load cases respecting the load time course.

This diploma thesis deals with creation of computational model of AZUB recumbent tricycle composite axle for stress strain analysis. The thesis consists of four main parts. The first part contains introduction to the offer of full suspended tricycles from the most known manufacturers. Furthermore it contains introduction to composite materials that makes the main element of AZUB´´s suspension, and the description of the AZUB´´s front axle. In the second part there is detailed compilation of computational model for purpose of stress strain analysis of three load states. The effect of specific material and geometry parameters on axle behavior is discussed with the aim of choosing the most appropriate variant. Third part deals with the manufacturing of the front axle prototype and with tests leading to input data for numerical model and verification of computational model. Modifications and changes that lead to manufacturing of the second prototype are content of the last part. Based on this experience some recommendations for future development of the numerical axle model and the front axle suspension itself are formulated.

Glass fibre composites are common materials used in high voltage applications as insulating materials that provide good structural integrity. The aim of this thesis is to develop a method of studying the failure in such materials by measuring the dielectric strength on micro- and meso- scale samples, consisting of single fibre filaments and fibre bundles respectively embedded in epoxy resin. To do this, a body of relevant knowledge has been amassed, which is complemented with finite element analysis giving detailed insight into the electric field distribution in the microstructure of fibre composites. A method of producing virtually defect free single fibre samples has been developed where a filament is hung down tubes and cast in epoxy resin. A similar method was developed for producing bundle samples, however this needs some slight correction in order to prevent exothermic reactions. The dielectric strength of these samples are measured by applying a continuously increasing voltage until discharge is recorded. To evaluate the method micro- and meso- scale samples were prepared of three different fibres and their dielectric strengths measured. This evaluation showed that the method can be used to measure a definitive lower bound in the dielectric strength of fibre composites. However, the method can not definitively determine the location of the discharge, which is necessary to verify conclusions about the materials properties. To progress the method, the dielectric strength of neat epoxy samples of the same dimensions as the fibre composite samples should be investigated. Increasing the tolerance of the measurement setup should also be investigated as this could help by increasing the power of the discharge leading to more severe damage in the material.