Variable-stiffness optimization of CFRP body panels for body-in-white

Body panels have a direct influence on the static and dynamic stiffness of the body-in-white. With the introduction of CFRP in automotive body, these panels have ushered in the potential of being designed with variable-stiffness. However, due to the inherent complexity of variable-stiffness design and the need to integrate all panels to account for their interaction on BIW, the related design issue has not been solved. This paper reports a design method to achieve the successive optimization of the thickness distribution and stacking sequence for body panels, as well as ensure basic manufacturing and blending requirements of design results. This method was applied to the virtual design of the roof, floor, outer and inner side panels of a body-in-white. Compared with original constant-stiffness CFRP components, a 16.4% weight reduction was attained, the torsional and bending stiffness, first-order torsional and bending frequencies were enhanced by 5.0%, 10.9%, 4.7%, and 7%, respectively.