可脱落式前副车架结构仿真与试验

为应对日趋严格的被动安全法规和标准以及当前流行的短前悬设计带来的整车前碰空间不足的问题，提出可脱落式副车架设计方案。首次引入三阶等效波设计方法，基于某车型Euro NCAP前部偏置碰撞仿真结果提取前副车架连接点位置的载荷特征曲线，规划可脱落式副车架的失效时域；设计前副车架脱落方式及其零部件试验方案，采用CrachFEM失效模型对试验方案进行仿真，对比5轮试验与仿真结果发现：CrachFEM失效模型仿真与冲击试验中前副车架的拉脱失效力峰值的误差最大值为4.31%。 将优选脱落结构设计方案应用于该车型Euro NCAP前部偏置碰撞仿真计算，前副车架在规划时域内脱落，第三阶等效加速度a3降低11.83%，整车位移增大20 mm，整车归零时刻延长1.1 ms，因此该方案可有效改善该车型的前部高速耐碰撞性能。

Simulation and test for detachable front sub-frame structure

As to the increasingly strict passive safety regulations and standards, as well as the lack of crash space resulted from current popular short overhang design for vehicle, a detachable sub frame design scheme is proposed. The equivalent triple trapezia wave design method is introduced for the first time, based on the simulation results of the Euro NCAP front offset impact of a certain vehicle, the load characteristic curves of the junction of the front sub frame are extracted, and the failure time domain of the front sub frame can be planned. The shedding mode of the detachable front sub frame is designed and its component test schemes are proposed, and the test scheme is simulated by CrachFEM failure model. The results of five times of tests and simulations show that the maximum prediction error of fracture load amplitude is 4.31% in CrachFEM failure model and impact tests; the superior shedding structure design scheme is applied to the vehicle model, and the numerical analysis of the Euro NCAP front offset impact simulation shows that, the front sub frame is detached in the planned time domain, the third platform equivalent acceleration a3 reduces by 11.83%, the maximum value of the vehicle displacement increases by 20 mm, the time when vehicle velocity becomes zero prolongs by 1.1 ms, and so the high speed front impact resistance of this kind of vehicle is effectively improved.