친환경 자동차의 후방 추돌 성능을 개선하기 위한 후방 차체 구조의 최적설계

Abstract

In this study, the rear structural optimization of the mid-sized sedan car body was performed based on the rear crash test method specified by FMVSS No.301 for improving the rear crash performance of eco-friendly automobiles. The sensitivity analysis was carried out in order to look for structural members that are extremely influential on rear crash. It was found that, among the rear structural members, the rear side frame was selected as the redesign target. In order to increase the buckling performance of the rear side frame, five design variables to the frame were selected primarily via topology optimization. Moreover, the five selected design variables were applied to the Box-Behnken experimental design to generate three response surface functions, including structural mass, rear crash intrusion, and vehicle interior acceleration. As the optimal design was performed by using the generated response surface functions, the cross-sectional shape, longitudinal dimensions, and plate thickness of the rear side frame were determined. By applying the obtained optimal design values to the base vehicle model, the rear crash intrusion and the vehicle interior acceleration were reduced by 9.7 % and 5 %, respectively, as compared to the base vehicle model.