钛合金整体隔框等温成形局部加载分区研究

Simulation on local loading partition during titanium bulkhead isothermal forming process

钛合金大型整体隔框在航空航天领域得到了越来越广泛的应用,等温局部加载为这类构件的成形提供了新的途径。等温局部加载过程复杂并且存在着加载区、未加载区和过渡区以及不同加载区之间的转换,合理的局部加载分区,是保证成形过程实施和成形质量的关键,文章研究并提出了局部加载分区的总体原则,随后基于DE-FORM3D有限元软件,采用数值模拟方法研究了局部加载分区(大小、位置)对TA15钛合金整体隔框成形过程的影响规律。结果表明,局部加载分区对未加载区材料错移的影响是短程效应,合理的分区可有效控制未加载区材料错移和降低总体成形载荷;分区对材料总体变形量和变形均匀性影响不大;采用筋上分区有利于提高筋的充填性能并可避免毛刺的产生,从而可提高了过渡区成形质量。

Lager-scale integral bulkheads of titanium alloy are widely used in aviation and aerospace industry, isothermal local loading forming has provided a new approach to form them. However the isothermal local loading process is very complicated and there exists loading, unloading and transitional zones and the alteration between different loading zones. The partition of loading zone is the key for the process realization and forming quality. In this paper the principle for local loading partition is analyzed and proposed, then based on the DEFROM3D software, the local loading partition （form, size and position） and their effect on laget-scale integral bulkheads of titanium alloy isothermal forming are investigated. The results show that the influence of partition on the shift of unloading zone is a short range effect, proper partition could effectively keep the shift in an acceptable range and reduce the whole forming load, the partition has little effect on the whole deformation uniformity and forming quality. Partition along the rib of bulkhead is good for filling of ribs, reducing the burrs further to improve the quality of transitional zone.