铝合金热冲压板件多目标优化

Multi-objective optimization of hot stamping of aluminum alloy blank

为解决铝合金热冲压板件存在的减薄和回弹等缺陷,采用响应面法分析了板料初始成形温度和压边力对最大减薄率和最大回弹量的影响规律。结果表明：成形件的最大减薄率随着板料初始成形温度和压边力的增大而增加;最大回弹量随着板料初始成形温度和压边力的增大而下降。最大减薄率和最大回弹量之间具有一定的冲突性。为解决这种冲突,采用多目标遗传算法NSGA-II进行多目标优化,得到Pareto最优解。进而在保证最大减薄率和最大回弹量都相对较小的情况下,确定合理的铝合金热冲压板件的工艺参数范围：板料初始成形温度为470.86~520°C;压边力为110~131.78k N。试验结果表明,合理的工艺参数可以避免破裂和减少回弹。仿真结果与试验具有较好的一致性。

To overcome the defects of thinning and springback in aluminum alloy hot stamping,the response surface method was employed to analyze the effects of initial blank temperature and blank holder force（ BHF） on the response values,namely,the maximum thinning rate and maximum springback value. The results show that the maximum thinning rate increases and the maximum springback value decreases with increasing initial blank temperature and BHF. Conflict exists between the maximum thinning rate and maximum springback value. In order to resolve such conflict,multi-objective optimization was conducted by genetic algorithm（ NSGA-II） to reach a Pareto optimal solution. To keep both the maximum thinning rate and the maximum springback value at a relatively lower level,the optimal ranges of process parameters were determined： initial blank temperature： 470. 86 ~ 520° C; BHF：110 ~ 131.78 k N. The results show that reasonable process parameters can avoid cracks and decrease springback.The simulation results agree well with the experimental results.