Parametric design and modeling method of CFRP laminated components applicable for multi-material vehicle body development

Abstract

Combined application of steel, aluminum and CFRP is the main direction of future lightweight body development. However, the anisotropy and additional lamination design variables of CFRP parts poses significant challenges for the development of multi-material bodies. This study establishes a parametric design method for the variable-thickness lamination scheme based on non-uniform rational B-splines (NURBS), it can be coupled with existing parametric design methods for structural shapes to formulate a complete parametric design and modelling of CFRP components. On this basis, a homogenized intermediate material property is derived from classic laminate theory by introducing lamination assumptions, it enables a stepwise multi-material body optimization method to solve the challenge that components’ material design variables switching between CFRP and alloy will introduce/eliminate lamination design variables iteratively, posing a great optimization convergence difficulty. The proposed parametric modeling method for CFRP components was validated by experimental tests of a fabricated roof beam, and the proposed optimization method was applied to a vehicle body, achieving 15.9%, 23.9%, 18.6%, 12.2% increase in bending and tortional stiffness and modal frequencies; 20.2%, 9.3%, 12.7% reduction of weight and peak acceleration in frontal and side collisions. This study enables the forward design of multi-material bodies compatible with CFRP parts.