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1	Finite element modeling of arc welded joint based on the experimental studies of the weldment Tanha, Tamrin 14 October 2016 (has links) The structural integrity of a welded structure depends mainly on the performance of the welded joints. Due to the welding process, the mechanical properties of the structure change and different regions are created in the weldment. The mechanical properties of welded joints change significantly around the heat affected zone (HAZ). So to predict stress distribution around the weld, these changes should be considered in the finite element model (FEM) of the welded structure. In this research, the changes of mechanical properties around the welded joint were experimentally tested and used to develop a FEM model of a welded joint which can predict the stress behavior around the weld. First, an experimental analysis was carried out on an ASTM standard arc welded joint of stainless steel specimen to observe the microstructural change in the HAZ. This enables to find out the HAZ width using an optical microscope. Moreover, a tensile testing was performed to investigate the change of Young’s modulus of the HAZ compared to the base metal (BM). Another experimental analysis was also performed on a real arc welded structure of the same material to observe its’ strain distribution around the HAZ. The HAZ width and Young’s modulus obtained from the experimental testing were then applied to generate the FEM model of an ASTM standard arc welded joint as well as a real arc welded structure of stainless steel. The finite element analysis (FEA) results of stress distribution around the weld joint in both cases show a good agreement with the experimental results. Therefore, the developed material property based FEM model can predict the stress behavior of similar type of structures with the same welding process on the same material studied in this research. / February 2017 Welding, HAZ, FEM, FEA
2	Universell dragprovmaskin : För dragprov av tillverkade produkter Karlsson Lillienberg, Emil, Holgerson, Rasmus January 2024 (has links) In this bachelor thesis we will present our development and design of a universal tensile testing machine made for FA-TEC i Falkenberg AB capable of creating a pulling force of 1 MN which is approximately equal to a load of 100 tonnes. The purpose of the machine is to allow for the company to further their inhouse capabilities of tensile testing of their diverse steel products, allowing them to streamline and reduce delivery time and cost. The goal is for FA-TEC to be able to assemble the construction themselves in their metal workshop and put the machine into use this fall 2024. The project focuses on the design process and how and why we make different choices in reference to different perspectives such as safety in the form of solidity of the design and work environment. We also have a requirement specification as well as other limiting factors like available equipment for construction, subcontractors production catalog, work space and a deadline. The methodology we used is inspired by the method from the book “Product Design and Development” by Karl T. Urlich, Steven D. Eppinger, and Maria C. Yang. Chosen methodology is crossed by product development and semantic discontinuity detection by using FEA to conduct calculations of the construction giving us valuable feedback we can use to optimize and change the design, this is then done in multiple iterations until we arrived at our final design. FEM FEA MLA Dragprov Maskin Maskinteknik Mechanical Engineering Maskinteknik
3	Využití optimalizačních algoritmů při návrhování konstrukcí / Using Optimization's Algorithms by Designing of Structures Fedorik, Filip Unknown Date (has links) The application of optimization algorithms in the design of many economical and industrial problems currently represents a significant assignment. The development of high-powered computers allows an application of difficult mathematical techniques and physical phenomena to simulate real problems with sufficient accuracy. The optimization techniques used in engineering designs are mostly represented by modified mathematical programming methods with extension of their usability. The aim of the presented thesis "Using Optimization´s Algorithms by Designing of Structures" is to analyze the applicability of optimization procedures which are available in the widely used computing system ANSYS in civil and mechanical engineering practice. The numerical analyses were performed within the frame of multi-extreme, one to three dimensional optimization problems, multi-dimensional problems expressed by minimizing the weight of a truss beam and efficient design of air gap location in wooden studs from the point of view of thermal features of the structure. The analyzed optimization processes are in plurality verified with accurate manual computing and graphical solutions and the accent is put on optimization methods´ possibilities to improve robustness, efficiency and accuracy of the optimization algorithms in civil engineering problems´ designs. The optimization methods represent a suitable approach to improve the efficient design of a wide range of civil and mechanical engineering structures and elements. By combination of their advantages and FEM/FEA method it is possible to achieve very good results, although robustness of the solutions is not guaranteed. The robustness and accuracy of the procedure could be increased by competent exploration of design space and suitable selections of optimization methods´ features.
4	Vytvoření databáze tuhosti statorových svazků elektrických strojů točivých / Creation of database of stator core stiffness of rotational electrical machines Podzemný, Zdeněk January 2013 (has links) In this thesis is wrote up a complete procedure of stator core stiffness determination using finite element method (FEM), subsequently, the stator core stiffness database was created according to this procedure. In the next chapter is carried out a sensitivity analysis of one chosen stator core, which led to identifying parameters that affected its stiffness the most. Finally, a modal analysis of one synchronous machine was performed using FEM, in order to determine the effect of stator core stiffness on modal characteristics of the machine. Several modal shapes and corresponding natural frequencies were computed in this analysis, then only a few shapes with the highest core effect were chosen and compared.
5	Electrohydrodynamic Microfabricated Ionic Wind Pumps for Electronics Cooling Applications Ongkodjojo Ong, Andojo 08 March 2013 (has links) No description available. Theoretical Physics Design Electrical Engineering Electromagnetics Energy Engineering Experiments Fluid Dynamics Materials Science Mechanical Engineering Physics Plasma Physics Solid State Physics Systems Design ionic wind pumps thermal management MEMS electronics cooling corona discharge electrohydrodynamics heat transfer coefficients coefficient of performance (COP) FEM/FEA optimization lifetime test microfabrication process

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