汽车铝合金前防撞横梁服役性能仿真及优化设计

Simulation and optimization design of service performace of vehicle aluminum alloy front anti-collision beam

以壁厚为设计变量,以碰撞安全性能优于原钢制横梁为设计约束,采用遗传算法开展了铝合金前防撞横梁设计及多目标优化。结果表明,在100%和40%重叠刚性墙低速碰撞工况下,原钢制前防撞横梁的碰撞支反力峰值、最大碰撞侵入位移和最大有效塑性应变分别为29.25和24.29 kN、36.84和39.80 mm以及0.30和0.21,存在开裂风险。总质量、最大碰撞侵入位移和碰撞支反力峰值响应对铝合金前防撞横梁后端面和前端面的壁厚变化较为敏感,而最大有效塑性应变响应则对垂向加强筋和横向加强筋的壁厚变化较为敏感。在100%和40%重叠刚性墙低速碰撞工况下,Pareto最优解的各项性能较原钢制前防撞横梁均有不同程度提升,最大碰撞侵入量分别降低了26.9%和40.7%,最大有效塑性应变分别降低了75.7%和52.4%,碰撞支反力峰值分别提升了43.6%和22.6%,实现了铝合金前防撞横梁总质量减重4.73 kg,减重54.8%。

Taking the wall thickness as the design variable and the collision safety performance better than that of raw steel beam as the design constraint,the design and multi-objective optimization of aluminum alloy front anti-collision beam were carried out by genetic algorithm.The results show that,under the low-speed collision conditions with 100%and 40%overlapping rigid walls,the peak reaction force,the maximum collisional intrusion displacement and the maximum effective plastic strain of raw steel front anti-collision beam are 29.25 and 24.29 kN,36.84 and 39.80 mm,0.30 and 0.21,respectively,and there are cracking risk.The responses of total mass,the maximum collisional intrusion displacement and the peak reaction force are sensitive to the wall exists thickness change of the rear and front faces of aluminum alloy front anti-collision beam,while the responses of the maximum effective plastic strain is sensitive to the wall thickness change of the vertical and lateral stiffeners.Under the low-speed collision with 100%and 40%overlapping rigid wall,the per-formances of Pareto optimal solution are improved in different degrees compared with that of the raw steel front anti-collision beam.The maximum collisional intrusion displacement is reduced by 26.9%and 40.7%,respectively.The maximum effective plastic strain is re-duced by 75.7%and 52.4%,respectively.The peak reaction force is increased by 43.6%and 22.6%,respectively.The total mass of a-luminum alloy front anti-collision beam is reduced by 54.8%with 4.73 kg.