TC4钛合金空心结构风扇叶片的鸟撞动力学响应及损伤失效

Dynamic Response and Damage Failure Behavior of TC4 Titanium Alloy Hollow Fan Blade

航空发动机是鸟撞事件中的高概率、高危部件,对风扇叶片相关抗鸟撞问题的研究具有重要意义。采用三维数字图像相关(3D-DIC)法开展了TC4钛合金空心结构风扇叶片在不同高度下的静置鸟撞试验。此外,基于Johnson-Cook动态本构模型与损伤失效理论建立了相关计算模型,较好地描述并验证了航空发动机风扇叶片在鸟撞过程中的动态变形响应过程与失效情况。结果表明:鸟撞速度的变化主要影响叶片变形的量级,而不会引起叶片特征模态的改变;在鸟撞过程中,叶根是应力/应变局域化显著区域,更容易发生损伤失效;随着鸟撞位置的提高,空心结构风扇叶片在叶根处失效断裂对应的临界鸟撞速度逐渐提高,整体结构抗鸟撞性能越好。试验结果及相应的数值模拟为TC4钛合金空心结构风扇叶片的抗鸟撞设计提供了一定的参考。

Aero-engine is a high probability and high-risk component of bird strike events,which is of great significance to the study of bird strike resistance of fan blades.In this paper,based on the three-dimensional digital image correlation(DIC)in-situ strain measurement method,the static bird strike tests of TC4 titanium alloy hollow structure fan blades at different heights are carried out.In addition,a simulation model is established based on Johnson-Cook dynamic constitutive model and damage failure theory to better verify and describe the dynamic deformation response process and failure situation of aero-engine fan blades during bird strikes.It is found that the variation of bird strike velocity mainly affects the magnitude of blade deformation,but does not cause the change of blade characteristic mode.In the bird strike process,the middle root is a significant area of stress/strain localization,which is more prone to damage failure.It is found that with the increase of bird impact position,the critical bird impact velocity corresponding to the failure of the hollow fan blade at the blade root increases gradually,and the bird impact resistance of the whole structure is better.This experiment and the corresponding simulation study provide a certain reference for the anti-bird impact design of the TC4 titanium alloy hollow structure fan blade.