摘要
某型风扇叶片工作后在凸肩工作面发现裂纹,断口分析后判断为疲劳裂纹,起始于盆侧凸肩工作面下侧靠近尖部边缘。建立凸肩工作面接触模型,分析了凸肩工作面挤压应力分布和位移变形,并对其压痕和磨痕进行了检查。结果表明:裂纹起始位置存在局部挤压应力集中。由于叶片工作载荷和凸肩初始紧度导致的凸肩变形错位而形成不均匀接触;同时凸肩工作面的初始装配错位和边缘倒角较小进一步加剧了裂纹起始位置的挤压应力集中程度,较大地局部挤压应力导致凸肩工作面耐磨涂层在工作过程中出现微裂纹,进而形成初始裂纹,在振动应力作用下,最终扩展到基体。
A crack appears on a shrouded fan blade contact surface after operation,which is fatigue cracks originated from shroud contact surface underside edge near the fan balde tip. On the use of shroud contact surface models, the distribution of extrusion stress and dislocation deformation were analyzed,and the indentation and scar were checked on the shroud contact surface. The results show that local extrusion stress concentrates on the initial crack location, which results from shroud deformation dislocation induced asymmetry contact due to fan working loadings and shroud initiation tightness. The extrusion stress concentration of the shroud deformation dislocation is further intensified by the initiation assembly dislocation and little edge chamfer on the shroud contact surface. The micro-cracks appeared on wear- resistant coating of the shroud contact surface during the operation, and then formed the initiation crack, which extended to the shroud matrix finally by vibration stress.
出处
《航空发动机》
2015年第6期44-48,共5页
Aeroengine
基金
航空动力基础研究项目资助
关键词
凸肩工作面
裂纹
挤压应力集中
装配错位
倒角
风扇叶片
shroud contact surface
crack
extrusion stress concentration
assembly dislocation
chamfer
fan blade
