中文摘要：

针对仿真中难以简单判断7075铝合金热成形失效的问题,引入损伤因子作为评判失效的参数。首先,建立了7075铝合金高温损伤本构方程。随后,使用FORTRAN语言编写Ls-dyna用户自定义材料子程序,对B柱进行热成形有限元分析,研究单一参数变化对B柱成形最大损伤值的影响。最后,利用正交实验分析对成形参数进行优化,最终确定了一组最优成形工艺参数组合：板料初始温度420℃,模具初始温度60℃,摩擦因数0.15,压边力6 000N,冲压速度230mm/s。

英文摘要：

To overcome the difficulty in judging the thermoforming failure of 7075 aluminum alloy, a dam-age factor is introduced as a failure judgment parameter. Firstly, the thermal damage constitutive equation of 7075 aluminum alloy is established, with a corresponding user-defined material subroutine in Ls-dyna created with FOR-TRAN language. Then a finite element analysis is conducted on the thermoforming of B pillar to study the effects of single parameter change on the maximum forming damage of B pillar. Finally, the forming parameters are optimized by using orthogonal experiment, and a set of optimal parameters of forming process is determined： an initial sheet temperature of 420℃, an initial die temperature of 60℃, a friction coefficient of 0 . 15 , a blank-holder force of 6000N and a stamping speed of 230mm/s.