Abstract:

A reliability-based design optimization method was presented based on the sequential Kriging method to decrease the computational intensity and to improve the accuracy of the traditional reliability-based design optimization of automobile body structure for the lightweight design of vehicle body. The vehicle mass was selected as the objective of optimization, and the crashworthiness responses were chosen as the reliability constraints to establish the reliability optimization design model. The sampling data of finite element model forvehicle frontal crash was generated and calculated by using the Latin hypercube design of experiment, and Kriging models for objective and constraint functions were built up according to the simulation results to improve the computational efficiency. The sequential optimization and reliability assessment (SORA) method was used to decouple the nested optimization into a single level optimization. On each iteration, a performance measure method was adopted to evaluate probabilistic constraints based on Kriging model to enhance the computational accuracy. The results show that the method can meet the needs of the efficiency and accuracy for the engineering design, and meet the reqirements of automotive safety, light weight and reliability. The vehicle mass is reduced by about 1.4%.

Key words:  vehicle body lightweight, crashworthiness, Kriging model, reliability-based design optimization, sequential optimization