激光喷丸强化是利用高能短脉冲激光和材料相互作用诱导的冲击波压力使材料表面改性的技术,适度残余应力场分布对应着特定的强化效果,需要优化的激光喷丸轨迹来实现。连续激光喷丸过程中冲击波压力及其残余应力的变化很难用实验来测量分析,导致强化过程不能有效控制。采用数值分析技术,在激光喷丸有限元建模的基础上,解决了脉冲激光束连续逐点喷丸强化的模拟轨迹控制。以连续单点单次和单点多次激光喷丸6061-T6铝合金为研究对象,对冲击波压力传播、应力分布及表面曲度变化进行数值分析,揭示激光喷丸强化中激光冲击波传播及应力变化内在的相互关系,为激光喷丸实验过程中参数优选和表面质量的有效控制提供理论依据。

Surface modification induced by laser shock peening (LSP) is a new technique realized by laser induced shock wave on the surface of metal,appropriate residual stress distribution corresponds to specific strengthening effects,which can be achieved by the optimized laser peening path. Usually,measurement analysis on the change of shock wave pressure and residual stress induced by laser continuous shock peening are hard to carry out,this causes difficulty to control the strengthening process effectively. In this paper,based on the numerical analysis technology,finite element model of LSP is established,and the pathway controlling of continuous point-to-point pulsed laser shot peening is settled. Taking single and multiple LSP process of 6061-T6 aluminum alloy as a research object,numerical analysis are carried out to investigate shock wave propagation,stress distribution and the change of surface roughness. The relationship between laser shock wave propagation and stress changes during LSP process are disclosed,which can offer theoretic basis for optimizing parameters and controlling surface characters effectively during laser peening process.