基于理论推导的前端结构耐撞性设计

Design of front structural crashworthiness based on a theoretical derivation method

为使车身结构耐撞性开发工作更早地介入到项目开发中来,并获得理想的前端结构压溃模式以及碰撞波形,推导了前端结构断面力以及长度的理论方法。引入三阶等效波形的设计方法,将碰撞波形分为:吸能盒压溃阶段﹑纵梁前端压溃阶段﹑纵梁后端以及前围侵入3个阶段;分别设定每个阶段前期的波形目标,推导结构的断面力;依据能量守恒原理,推导每个阶段结构的长度。仿真验证了该推导方法。结果表明:用本方法推导的断面结构可以实现理想的轴向压溃模式。因而,用该方法可以在概念设计阶段有效地确定车身结构的关键设计参数,尤其适用于完全正向开发车型。

A theoretical derivation method was described for calculating the front structure＇s length and section force of a positive development vehicle to move structural worthiness design forward to the conceptual design phase and to obtain desired deformation behaviors of front structures and an ideal impact pulse. A 3-step equivalence crash pulse design method was used. The 3-steps were the crash-box deformation step, the front member deformation step, and the rear member and dash intrusion step. The 3-step structure＇s section forces were derived by a 3-step pulse target which was set in the prophase The 3-step structure lengths were derived ccording to the energy conservation principle. The method was validated by numerical simulation. The results show that the front structure has an ideal behavior of axial deformation. Therefore, the method can provide the critical design parameters effectively in the conceptual phase with the method being especially suit for a positive developing vehicle.