This paper on "Design Optimization of Vehicle Structures in Nonlinear Regions" was presented at the NAFEMS World Congress on Effective Engineering Analysis - 25-28 April 1999, Newport, Rhode Island, USA.

Abstract

This paper presents the application of a finite element optimization package to study the design of vehicle structures with nonlinear characteristics. A study of an existing production vehicle B-pillar structure was undertaken to demonstrate how to increase its upper lateral load carrying capability by a factor of ten. The COSMOS/M finite element optimization software was used to adjust the shape and material characteristics simultaneously while minimizing weight. Two approaches were considered for optimizing the structure. In the first approach, the structure was optimized using the nonlinear static analysis and the parametric optimization capability of the software. In the second approach, the structure was optimized using the linear static and buckling analyses while utilizing the parametric optimization capability of the software followed by a nonlinear analysis. The results from either approach show that the weight and cost necessary for a ten-fold improvement in the load carrying capability were very low. The computational time for the second approach was a fraction of the time needed for the first approach. Further, the results illustrate how structural design optimization using the finite element method can be effectively utilized for use in an integrated design and analysis process.