斜激光冲击对航空发动机风扇轴弯曲疲劳性能的影响

Effects of oblique laser shock processing on rotary bending fatigue of aero-engine fan shaft

  • 摘要: 采用激光斜入方法对航空发动机扇轴转接圆角部位进行激光冲击强化试验。分析了斜冲击机理及方法,计算优化斜激光冲击强化试验参数,对冲击前后试件的显微硬度、残余应力进行对比分析,并进行旋转了弯曲疲劳对比验证试验。其结果表明,风扇轴经过激光斜冲击强化后,表面显微硬度提高了11%,残余应力不均匀性得到改善,旋转弯曲疲劳寿命提高了160%;断口观察分析可知,激光冲击强化可以使疲劳源位置内移,降低裂纹扩展速率,从而提高试件的疲劳性能。

     

    Abstract: The circular bead of aero-engine fan shaft was obliquely shocked by laser shock processing(LSP). The shocking parameters were determined according to the analysis of the oblique laser shock model. After being obliquely laser shocked, the surface residual stress and micro-hardness of the aero-engine fan shaft were investigated and analyzed. Besides, the rotary bending fatigue tests and fracture analysis were also conducted. The experimental results show that the micro-hardness of the fan shaft increased about 11% by laser shock processing, which modified the inhomogeneity of the surface residual stress, and the rotary bending fatigue life of fan shaft increased by 160% after LSP. The fracture analysis show that the location of fatigue initiation migrated to a inner place of materials and the crack growth speed of fan shaft reduced by LSP, which is necessary for improving the fatigue life.

     

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