基于碰撞性能的车身刚度链设计方法

A Design Method of Car Body Stiffness Chain Based on Crashworthiness

本文中综合考虑车身动态与静态刚度和正面碰撞安全性,提出了一种车身正向概念设计方法。首先,根据车身A级面和整体布置,建立了车身简化几何模型,确定了19个车身主断面,并基于梁单元理论和传递矩阵法建立车身刚度链数学模型。接着,采用碰撞经验公式设计矩形前纵梁,以等效静态载荷模拟车身正面碰撞动态加载,并提出了基于等效静态加载条件下的车身变形要求。然后,以车身质量最轻为目标,车身静态刚度、1阶模态和碰撞变形为约束,采用遗传算法优化车身各梁单元主断面参数。最后对某一近似标杆车进行有限元仿真,计算其车身静刚度与模态,与本文中的刚度链方法计算结果进行对比,验证了该方法的可行性。

Concurrently considering the dynamic and static stiffness and frontal crash safety,a forward conceptual design method of car body is presented in this paper. Firstly according to class A surface and vehicle general layout,a simplified geometric model for car body is established,19 main cross-sections of the body is determined,and the stiffness chain model of car body is built based on beam element theory and transfer matrix method. Then rectangular front longitudinal beam is designed by using collision empirical formula,the frontal crash dynamic loading of car body is simulated by equivalent static load,and the requirements of car body deformation are put forward based on equivalent static loading condition. Next,a simulation on the main cross-section parameters of each beam element of car body is conducted by using genetic algorithm,with minimizing car body mass as objective and the static stiffness,the first order mode and collision deformation of car body as constraints. Finally,a finite element simulation is performed on an approximate benchmark car,with its static stiffness and vibration modes of car body calculated and compared with that by using stiffness chain method,verifying the feasibility of the method adopted.