厚度幂指数分布管状结构耐撞性设计准则与方法研究

厚度或质量连续分布技术对车身薄壁结构的轻量化和性能设计有着非常重要,甚至起到决定性的作用,从设计方法上研究连续变厚度结构在车身零部件中的耐撞性应用是安全性设计所需的主要工作。本文研究一种较新颖的薄壁吸能结构,其管壁厚度按照幂指数形式连续分布,根据此分布特点推导出了该薄壁结构在等质量条件下与其他管状结构(比如均匀管、拼焊管和锥管等)之间相关参数的定量解析关系,给出了前者的耐撞性设计准则,评估了不同梯度对幂指数管耐撞性能的影响。分析结果显示,该新颖管状结构比其他截面管具有更理想的耐撞特性。然后,在2个设计区间内对梯度指数分别采样并构造近似模型,采用遗传算法作为求解器得出了非劣解前沿,研究发现高阶响应面近似模型得到的设计结果不一定是最优的。

Study on crashworthiness design criteria and method of tubular structures with power exponent distribution of thickness

The property of continuous thickness or weight distributions plays an important even decisive role on the lightweight and performance design of an automotive body. The main study of safe design for continuous thickness components is to investigate on their crashworthiness in the crash process of automotive structures. We studied on a new energy-absorbed thin-walled structure with the thickness distributed according to the power exponent function. The analytical relationships of the relative parameters among the new structure, uniform thickness tubes, tailor welded tubes and taped tubes were obtained. And the crashworthiness design criteria was also carried out. The parametrical study shows that the crashworthiness of the new tube is superior to those of other cross-sectional tubes. Then, the crashworthiness design method of the new tube was performed. The graded exponent was given at two design regions and was sampled to construct reasonable approximate model. The compared results demonstrates that the optimal results of the higher model are not necessarily to be best. In addition, the crashworthiness of thethin-walled structures could be enhanced by reasonably designing the tube thickness.