多目标遗传算法在整车轻量化优化设计中的应用研究

采用D－最优试验设计方法对汽车前部关键吸能部件的材料和板料厚度进行多参数空间的样本数据设计;为提高计算效率，将能够代表整车正面碰撞过程的高精度多参数近似模型引入到整车轻量化优化设计中，并利用多目标遗传算法对近似模型进行优化，使得车身前部吸能部件的板料厚度和材料得到合理配置，同时也使得整车质量和B柱加速度尽可能最小。在车辆安全性满足CMVDR294安全法规的同时，也在一定程度上减小了整车的质量。

Analytical Synthesis for Single Closed-loop and one DOF Over-constrained Mechanism 

Based on the calculation formula of the degree of freedom(DOF) for spatial mechanisms and screw theory, the relationship among the number of constraints,kinematic pairs and DOF of single closed-loop over-constrained mechanism with one DOF was analyzed.Then,by using virtual principle and analytical method,the constraint force and coupling with independent constraint number:one,two and three, respectively as well as synthesis condition with arbitrary combination were studied.Given specific constraint combination,the condition of satisfying non-instantaneous motion was analyzed,the number and arrangement of kinematic pairs and spatial geometrical assembly condition of
pairs’axis layout were presented,additionally,typical mechanisms were illustrated.