Optimized Development Process for Cast Components

Licentiatavhandling, 2005

In developing trucks, cast components of low weight and high durability need to be developed and produced. Cast components represent an estimated 10-15 percent of the total weight of a truck. There is a strong coupling between the production process and the mechanical properties of a cast component such as it's strength. Bearing this coupling in mind is an important element in the design process. A generic strategy for the optimal design of cast components, taking account of complex multi-physics problems and involving analyses of successively increasing complexity, is discussed. The term Level-Of-Detail (LOD) is introduced allowing the requirements on models at different stages in the development process to be described in a structured manner. Several investigations within this context illustrating and clarifying the basic ideas involved are presented. First, the sizing optimization of a model component with respect to both the mechanical and to thermal response is taken up as an example of analysis at a low LOD level. A novel thermal measure for production fitness is introduced here. Secondly, a topology optimization is presented as an example of a medium-level LOD analysis. Thirdly, a novel formulation of the thermo-metallurgical problem within casting, involving the modelling of solidification and the segregation of species, is considered as an illustration of analysis at a high LOD level. An efficient finite element formulation of the coupled problem in space-time terms is also developed and investigated.