7075铝合金激光多点冲击诱导残余应力的数值模拟  

Numerical Simulation of Residual Stress Induced in 7075 Aluminum Alloy by Repeated High-Power Laser Pulses

作　　者：张兴权[1] 李欢[1] 黄志来[1] 张鑫[1] 佘建平[1] 章艳[1] 段士伟[1] 

机构地区：[1]安徽工业大学机械工程学院,安徽马鞍山243002

出　　处：《中国激光》2015年第12期72-80,共9页Chinese Journal of Lasers

基　　金：国家自然科学基金(51175002);安徽省自然科学基金(090414156)

摘　　要：激光冲击强化技术是一种新型的材料表面改性技术。在实际应用中,由于激光光斑直径通常在20 mm以下,工件表面大范围的激光冲击强化需要采用多个光斑搭接。运用实验和数值模拟的方法,探讨了光斑在不同中心距下诱导的残余应力场的分布规律,研究了不同搭接率对残余应力分布的影响,以及两种不同加载顺序下表面残余应力的分布特性。结果表明:相邻光斑中心距对两光斑之间区域的残余应力有重要影响,随着两光斑中心距的减小,相邻光斑之间区域的应力场由残余拉应力转变为残余压应力;搭接率越大,获得的残余压应力幅值越大,残余应力分布越均匀;从中间到两侧的多点冲击方式能获得较大、较均匀的残余压应力。Laser shock peening （LSP） is a novel surface modified technique. In practical applications, due to the diameter of laser beam smaller than 20 mm, the overlapping LSP technology needs to process workpiece surface with large area. The residual stress fields induced by laser spots in different center distances are discussed with finite element methods and experiments. The influences of overlapping rate on the distributions of residual stress are investigated. The characteristics of residual stress distributions induced by different shocking sequences are also analyzed. The results show that the center distances of laser spots have significant influences on the residual stress of region between two laser spots. With the center distances of two laser spots decreasing, the residual stress fields at the region between two laser spots turn from tensile residual stress into compressive residual stress. The magnitude of compressive residual stress is increased with the increment of laser spot overlapping rate, and the distributions of residual stress generated by larger overlapping rate are more uniform. The multiple shocking sequence of mid-left-right can induce a large and uniform compressive residual stress field.

关 键 词：激光技术 残余应力 有限元分析 搭接 

分 类 号：TN249[电子电信—物理电子学]