控制厚度分布的正反向超塑胀形的有限元分析

为研究正反向超塑胀形工艺对厚度分布的影响,应用商业有限元软件MARC对带有凹槽的深盒形7475合金零件正反向超塑胀形过程进行了有限元模拟,并对不同工艺条件下成形后零件的壁厚分布结果进行了分析.研究表明:正反向超塑胀形工艺是控制成形零件壁厚的有效途径,通过优化压力-时间曲线和反向胀形模具形状,明显改善了零件的厚度分布,达到了零件的设计要求;后处理直观地显示了该零件正反向超塑胀形的全过程,为成形提供了合理的方案;零件变形各阶段的应变速率控制在7475合金的应变速率范围内,证明压力-时间曲线设计合理.

Finite element analysis of direct-reverse superplastic bulging process for thickness distribution controlling

In this paper, a commercial software MARC is used to simulate direct-reverse superplastic bulging process of 7475 alloy deep box part with groove shape. Thickness distribution under different process conditions is analyzed. The results show the following conclusions. The direct-reverse superplastic bulging process is an effectual approach to control thickness distribution of parts. Through optimizing the curve of pressure-time and the shape of reverse bulging die, thickness distribution of the part is apparently improved and the design requirement of the part is satisfied. The whole process of the part's direct-reverse superplastic bulging is shown by post treatment. It provides a logical scheme for actual forming. The strain rate of each forming stage is controlled in the range of 7475 alloy's strain rate. This shows the design of pressure-time curve is reasonable.