钛合金叶片前缘的外物损伤残余应力数值分析

为研究航空发动机叶片外物损伤(FOD)位置残余应力的分布规律,根据真实叶片前缘特征设计了模拟叶片,基于Johnson-Cook本构模型,使用LS-DYNA软件仿真分析钢珠以不同角度冲击钛合金模拟叶片前缘的过程,对比仿真与相同试验条件下的空气炮模拟外物损伤试验的FOD损伤形貌与宏观尺寸,验证了有限元模型的正确性。提取仿真计算的不同入射角度对应的FOD位置残余应力分布,结果表明:钢珠以0°角入射时,钢珠冲击产生的接触力和变形能明显大于其他入射角度的情况,说明钢珠偏斜一定角度入射时造成的偏斜型缺口处的材料失效与变形不如外物正撞前缘形成的半圆型缺口严重;在FOD缺口底部尖端靠近入射表面区域存在明显的残余拉应力。随着入射角度的增大,残余拉应力区的范围逐渐扩大,残余拉应力最大值逐渐减小。

Numerical analysis on residual stress of foreign object damage on the leading edge of titanium alloy blade

In order to study the distribution law of residual stress on foreign object damage (FOD) position in aero engine blades, the simulated blades were designed according to the characteristics of the aero engine blade leading edge. LS-DYNA software was used to simulate and analyze the impacting process of titanium alloy simulated blade at different angles based on Johnson-Cook constitutive and failure models. The damage morphology and macro size were compared between simulating results and FOD test results to verify the correction of the finite element model. The simulated residual stress distribution at the FOD position corresponding to different incident angles was extracted. The results showed that when the incident angle of steel ball was 0°, the contact force and deformation energy were significantly larger than other incident angles, indicating that the material failure and deformation at the skewed notch caused by a certain incident angle impact were less serious than the semi-circular notch formed by the 0° incident angle impact. There was a significant residual tensile stress area at the FOD notch root near the incident surface. As the incident angle increased, the range of the residual tensile stress area gradually expanded, and the maximum value of the residual tensile stress decreased.