薄壁结构双侧异步激光喷丸强化试验研究

航空发动机压气机叶片是典型薄壁结构,通过激光喷丸强化在叶缘引入残余压应力,是提高其抗异物撞击能力,延长疲劳寿命的有效途径。为解决双侧同步强化方法存在的材料层裂损伤风险的问题,提出薄壁结构双侧异步激光喷丸强化方法。试验研究发现:单侧薄壁激光喷丸试验中,光斑功率密度的改变会使薄壁结构相对于激光入射方向呈现"∧"或"∨"两种扭曲变形趋势;另一面采用同样参数进行激光喷丸后,扭曲变形会恢复;合理采用激光喷丸参数,双侧异步激光喷丸强化与同步强化相似,可以在两侧表面均得到残余压应力场,并且扭曲变形能满足形状精度要求。

Experimental Investigation of Double-Side Laser Peening of Thin-Wall Parts With Alternate Side Laser Scanning

Aeroengine compressor blade is a kind of typical thin-wall structure.Laser peening (LP) has been proved to be an efficient surface treatment to improve the fatigue life of blades by inducing compressive residual stress.Laser peening on blades at present is usually conducted in a double-side simultaneous scanning method to avoid deflection,which brings the problem that shock waves from dual side meet at the center,resulting in spallation being at high risk to happen.In this paper,a double-side alternate laser peening method is proposed.The results of the experiments show that with the change of laser intensity,single-side laser peened thin-wall components can be made to bend toward or away from the laser beam with single-side.The deflection would recover with the other side laser peened in the same parameters.With proper laser peening parameters,similar distribution of residual compressive stress to the simultaneous method could be induced on the components,and the final deflection would be within the scope of the accuracy requirement.