摘要：激光喷丸强化是一种新型的表面处理技术，在航空、航天、国防装备等方面有着广泛的应用前景。本文根据实验工况创建有限元模型，对单点多次激光冲击过程进行模拟分析。为了准确反映OFHC铜在高应变率下的应力应变状态，靶材的本构方程采用基于金属塑性变形细观位错理论的G-Z模型。为了更好地反应激光喷丸高速、瞬时的动态过程，开发了一个合理的载荷模型模拟激光脉冲压力，通过Abaqus/Explicit用户子程序将本构方程和载荷模型导入有限元模型进行数值计算。定量研究了受喷靶体的表面形貌和残余应力场，在不同的激光功率密度下模拟的凹坑深度与实验结果吻合较好，随着激光功率密度和喷丸次数的增加，残余应力场分布趋于稳定。比较不同光斑直径下凹坑深度的模拟值与实验值发现：光斑直径的变化不仅影响激光功率密度的变化，也会影响激光脉冲压力持续时间的变化。
　　关键词：激光喷丸，高应变率，表面形貌，残余应力，G-Z本构模型

　　Abstract:Laser shock peening（LSP） is a new kind of surface treatment technology and has a broad application prospect in aviation, spaceflight and national defense equipment, etc. A model based on the experiments of LSP with impacting one point for many times is simulated. In order to reflect the stress-strain of OFHC copper accurately under the high strain rate, G-Z model based on the microstructural evolution during deformation is adopted as the constitutive equation of the target. In order to reflect the high-speed, instantaneous dynamic process of LSP well, a reasonable load model is developed to simulate the laser pulse pressure. The constitutive equation and the load model are inputted into the finite element model for numerical calculation by the user subroutine of Abaqus/Explicit. The surface topography and residual stress fields of the target are investigated quantitatively. Depths of the modeling dimples are consistent with the experiment results under the different laser power densities. Residual stress fields tend towards stability with the laser power density and impacting numbers increasing. Compared the modeling depths of dimples and the corresponding experiment values, it could be found that the variation of the laser spot diameter not only affects the laser power density, but also has an effect on the laser pressure pulse duration.
　　Keyword:laser shot peening（LSP），high strain rate,surface topography,residual stress,GZ-constitutive model
　　联系方式
　　王成：hpcwxg@zjut.edu.cn
 

责任编辑：赵泽南

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