Topology optimization of vehicle structures

Abstract: This thesis concerns topology optimization of vehicle structures. Vehicle structures are considered to be composed of beams joined together and the work has been focused on a method for beam topology optimization including joints.The method presented has been implemented in Matlab and simple examples as well as more realistic applications have been studied. The research work is presented in four papers.Paper I presents beam topology opt imization with flexible joints. Design variables on beam cross sectional geometries and joint properties are introduced. A generic joint element is formulated in order to do topology optimization and the compliance topology optimization problem is described and solved.Paper II is an extension of Paper I where the joints are more general with stiffness properties in different directions. The paper introduces also a way to find joint stiffness for the generic joints.Paper III is a short application paper where a bus structure is optimized using the method presented in Paper l and II.Paper IV, finally, presents an approach to optimize a frame structure with regard to cost as well as for compliance and mass as in previous papers. This multi-attribute optimization method is applied to a ten beam structure and to a larger application example.