Weight reduction design of multi-material vehicle components using level set-based topology optimization

Recently, in order to reduce the weight of automobile body, various researches for designing multi-material structures including lightweight materials in place of the existing steel are being conducted. This paper presents the application of the topology optimization method for weight reduction of multi-material vehicle components. The component design problem is formulated using the concept of level set-based topology optimization in order to derive precise design candidates of the multi-material structure beyond the level of simply determining the position of the lightweight material within the component. In this study, a p -norm function with a penalty factor that can control the composition ratio of each material within the total weight of the component is used as the objective function, so that designers in the industrial field can review various component designs through a simple parameter study. Even if volume fraction constraints for each material are not considered in the problem formulation, an optimal design can be obtained due to the design constraints on the mechanical stiffness of the component. The distribution of each material in the component structure is represented by using the multi-material level set method and optimized by the topological derivative to minimize the p -norm function. The optimal results for one benchmarking problem and three vehicle component design problems are shown to confirm the usefulness of the proposed formulation in the 3D design space and to present the effective range of the penalty factor value in practical use.