Case Study in Design: Generation of Design Knowledge for Vehicle Sub-frames Based on Finite Element Simulation

This article reviewed the present industrial practice and challenges facing the automotive industry in designing the complex suspension component – the sub-frame. It revealed that the lack of design knowledge in terms of generic geometry representations and design rules is the root of the current repetitive and time-consuming process in the design concept development. Based on a comparative study of a selected group of existing sub-frame designs, this work identified performance and manufacturing related geometrical features of sub-frames. These include geometrical related features (design constraints, configurations, structures, dimensions), performance related features (stiffness, strength, mass), and manufacturing related features (material, manufacturing and joining methods). Finite Element method was applied to investigate the effects of changing the configuration, structures and dimensions of sub-frame members on the stiffness characteristics. The important geometrical features that affect the sub-frame stiffness were identified and quantitative relationships between the main features and the performance were established. Based on the quantitative analysis, a decision making hierarchical tree with three layers of design decisions was proposed for the effective design of future sub-frames.