Design Process for Property Based Optimization of Vehicle Body Structures 2003-01-2755

Structural topology optimization is a truly interesting and important area, which has developed very rapidly and matured considerably in many fields. However, the use of topology optimization for global structures, using detailed design, is still tremendously time-consuming. From this perspective, the author sees the development of methods and tools to include optimization on simplified models during the design process as the most interesting and important step towards implementing structure topology optimization in the vehicle industry. In the design process, structures are broken down into beams and joints, and are described using a PBM (Property Based Model). Beams are described using a rectangular cross-section with the possibility of being changed in size, shape and orientation. Joints are described as flexible elements using a set of sub-elements called 2-joints that makes it possible for the joint model to change topology and stiffness. The objective function is minimization of structural compliance with constraints on structure mass. Design variables are cross-section parameters for the beams and parameters controlling the constitutive properties of the 2-joints. Two in-house tools have been developed to support the comparison between the detailed FEM model and the result from the optimization of the more simplified PBM. In this way the designer will be aided by a clearly defined design process and a set of supporting tool to help him work towards a good design.