A material selection method for a hybrid box-type bodyshell with cut-outs using an equivalent bodyshell model without cut-outs

Abstract

In this article, we suggest a theoretical weight-reduction method to partially substitute an alternative light-weight material for a material in a box-type bodyshell with cut-outs using a material selection method. The box-type bodyshell with cut-outs was simplified as an equivalent box-type bodyshell model without cut-outs, which is denoted as an equivalent bodyshell model and has the same vertical stiffness as the case with cut-outs. The thicknesses of the roof and the walls of the equivalent bodyshell model were then determined such that the deflection of the equivalent bodyshell model was equal to the sum of the theoretical deflections of each box-type bodyshell section with cut-outs under a distributed vertical load condition. Next, the material selection method for weight-reduction design was applied to the equivalent bodyshell model to derive the hybrid-type equivalent bodyshell model. Finally, a weight-reduction design of the box-type hybrid bodyshell with cut-outs was derived from the hybrid-type equivalent bodyshell model. To demonstrate this method, we derived a weight-reduction design of the under-frame in the box-type hybrid bodyshell with cut-outs and then compared the finite element simulation results of the derived weight-reduction design with the suggested theoretical results. The comparisons yielded good correlations. The proposed method was useful to reduce the weight of a hybrid bodyshell with cut-outs by changing materials.