Abstract: With the consideration of the characteristics of carbon fiber reinforced polymer (CFRP) composite, the original steel stiffening panel of B-pillar is substituted with CFRP, with the laminate optimized. Firstly on the basis of vehicle finite element model for side impact, the substructure model for B-pillar is decoupled, the dynamic model for substructure is used to conduct the material substitution and performance calculation of B-pillar stiffening panel, and the initial layup and thickness of the laminate are determined. Then to give full play to the advantage of designability of composites, the structural optimization method for composite is adopted to optimize the ply thickness, angle, and layup sequence of laminate. Compared with original vehicle structure, the CFRP stiffening panel of B-pillar achieves a significant lightweighting results with its crashworthiness remained unchanged

Key words: vehicle, side impact, B-pillar, CFRP