针对汽车纵梁前端的薄壁吸能圆管,进行了涉及半径与长度变量的形状尺寸参数化设计,提出对设计空间进行逐次拟合的方法,通过移动与缩放来不断更新与缩减整个设计空间,在新的设计空间中将试验设计、薄壁圆管的高精度近似模型以及小种群遗传算法相结合进行寻优.数值算例表明,最优设计不仅使薄壁圆管的吸能性得到改善,提高了优化设计的效率,而且还减轻了质量. Aiming at the thin-wall energy-absorbing circular pipe at the front of the automobile longitudinal beam, parametric design of shape and size involving radius and length variables is carried out. A method of successive fitting of the design space is proposed. The entire design space is continuously updated and reduced by moving and scaling , The experimental design, the high-precision approximation model of thin-walled circular tube, and the combination of small population genetic algorithm are optimized in the new design space.The numerical examples show that the optimal design not only improves the energy absorption of the thin-walled circular tube, Optimize the efficiency of design, but also reduce the quality.