一种直升机尾传动轴抗弹击损伤容限分析方法

A Damage Tolerance Analysis Method for Helicopter Tail Drive Shaft after Bullet Attack

关键词:  直升机  尾传动轴  损伤容限  损伤动力学  疲劳裂纹扩展

Key words:  Helicopter  Tail drive shaft  Damage tolerance  Damage dynamics  Fatigue crack growth

摘要:

为保障直升机被弹击后仍具备充足时间供直升机安全降落，亟需对弹击后传动轴进行损伤容限设计，确保其被击中后仍拥有足够的剩余疲劳寿命。本文提出了一种直升机尾传动轴抗弹击损伤容限分析方法，可有效预测弹击损伤后的疲劳裂纹扩展寿命。采用该方法对尾传动轴进行弹击动力学仿真分析；其次，发展一种非标准断裂韧度测试方法以获取尾传动轴的断裂韧度；给出一种非标准疲劳裂纹扩展试验方法以获得尾传动轴的疲劳裂纹扩展材料常数；通过建立尾传动轴弹击损伤三维裂纹扩展模型对疲劳裂纹扩展寿命进行预测；通过尾传动轴疲劳裂纹扩展试验对所提出方法的有效性进行验证。分析结果表明，在相同入射角条件下，切边入射导致的尾传动轴剩余疲劳性能普遍低于中部入射的；在相同的入射位置条件下，45°入射比0°入射导致的尾传动轴剩余疲劳性能低。

Abstract:

In order to ensure that the helicopter still has enough time to land safely after bullet attack， it is urgent to design the damage tolerance of the helicopter tail drive shaft to ensure that it has enough remaining fatigue life. A damage tolerance analysis method for helicopter tail drive shaft after bullet attack is proposed， which can effectively predict the fatigue crack growth life after bullet damage. Firstly， this method performs dynamics simulation analysis of bullet attack on tail drive shaft； secondly， a non-standard fracture toughness test strategy is developed to obtain the fracture toughness of the tail drive shaft； thirdly， a non-standard fatigue crack growth test strategy is given to obtain the fatigue crack growth material constant； then， the fatigue crack growth life is predicted by establishing a three-dimensional crack growth model of the tail drive shaft after bullet attack； finally， the effectiveness of the proposed method is verified by the fatigue crack growth test of the tail drive shaft. The analysis results show that under the condition of the same incident angle， the residual fatigue performance of the tail drive shaft caused by the cut-edge incident is generally lower than that of the middle incident. Under the same incident position， the residual fatigue performance of the tail drive shaft caused by 45° incidence is lower than that by 0° incidence.