강제 변위를 이용한 자동차 천정 구조물의 구조최적설계에 대한 기초 연구

Abstract

Many people are seriously injured each year in car rollover accidents. When a car rolls over and hits the ground, the roof structure has to maintain occupant survival space. The National Highway Traffic Safety Administration (NHTSA) proposes a regulation of strength requirements of the roof structure, FMVSS 216. Recently, the Insurance Institute for Highway Safety (IIHS) proposed the reinforced strength requirements of the roof structure. Studies have been performed structural optimization that considers the regulation for roof crush. Most previous studies have been using approximation methods such as the response surface method (RSM) due to difficulty of sensitivity calculations. However, the approximation method can give inaccurate solutions in highly nonlinear problems, and it has a limitation on the number of design variables. In this research, nonlinear dynamic response optimization of the roof structure is performed using the enforced displacement method. The proposed method consists of the analysis and design domains. The displacements from nonlinear dynamic analysis are used as the enforced displacements in linear static response optimization as a loading condition. The roof strength requirement is considered as reaction force constraints by following the reinforced regulation of IIHS. An example of nonlinear dynamic response optimization is solved by using the proposed method.