Optimization of Torsional Stiffness for Heavy Commercial Vehicle Chassis Frame

Abstract

The chassis frame is the backbone of a heavy commercial vehicle (HCV). Its main purpose is to securely carry the determined load under all designed operative situations. Thus, it should be rigid enough to withstand the various forces acting on it. The objective of this study was to develop a stiffness model to select an optimum cross section with determined torsional stiffness. Johnson's method of optimization was adapted to develop a stiffness equation and select a section with a determined torsional stiffness and a required mass constraint. The stiffness obtained from the developed stiffness model and finite element analysis (FEA) is a close match, which proves the validity of the proposed model. The section with the maximum torsional stiffness was used for frame-level optimization to improve the torsional and lateral stiffness of the overall chassis frame. The strain energy absorption capacity of the cross member improved by changing the section of the cross member. By using the optimized section, the torsional stiffness of the frame improved by 44% and a lateral stiffness of 10% was obtained. The Creo software was used for modeling and FEA was performed with the Hypermesh software.