激光冲击强化钢的残余应力数学建模分析

Mathematical modeling analysis of residual stress in laser shock strengthened steel

为分析钢在激光冲击强化后的残余应力,以SAPH420结构钢为例,进行激光冲击强化处理。用有限元和无限元结合构建钢残余应力的有限元模型,计算残余应力。结果表明:激光冲击的光斑搭接率为75%时,压应力约为814 MPa,激光冲击时间为3 500 ns时,内能、塑性能及弹性能分别约为65、60、10 mJ,激光冲击强化后钢表面平均硬度为350HV0.2,屈服强度和抗拉强度分别超过587.3 MPa和594.4 MPa,疲劳性能提升,残余应力影响的最大深度为0.35 mm,有利于提升钢的使用寿命。

In order to analyze the residual stress of steel after laser shock strengthening,SAPH420 structural steel was taken as an example for laser shock strengthening.The finite element model of steel residual stress was constructed by combining finite element and infinite element,and the residual stress was calculated.The results show that when the overlap rate of laser shock is 75%,the compressive stress is about 814 MPa.When the laser shock time is 3 500 ns,the internal energy,plastic property and elastic energy are about 65 mJ,60 mJ and 10 mJ respectively.After laser shock strengthening,the average hardness of steel surface is350HV0.2,the yield strength and tensile strength exceed 587.3 MPa and 594.4 MPa respectively.The fatigue performance improves,and the maximum depth of residual stress is 0.35 mm,which is conducive to improving the service life of steel.