摘要：激光噴丸強化是一種新型的表面處理技術，在航空、航天、國防裝備等方面有著廣泛的應用前景。本文根據實驗工況創建有限元模型，對單點多次激光沖擊過程進行模擬分析。為了準確反映OFHC銅在高應變率下的應力應變狀態，靶材的本構方程采用基于金屬塑性變形細觀位錯理論的G-Z模型。為了更好地反應激光噴丸高速、瞬時的動態過程，開發了一個合理的載荷模型模擬激光脈沖壓力，通過Abaqus/Explicit用戶子程序將本構方程和載荷模型導入有限元模型進行數值計算。定量研究了受噴靶體的表面形貌和殘余應力場，在不同的激光功率密度下模擬的凹坑深度與實驗結果吻合較好，隨著激光功率密度和噴丸次數的增加，殘余應力場分布趨于穩定。比較不同光斑直徑下凹坑深度的模擬值與實驗值發現：光斑直徑的變化不僅影響激光功率密度的變化，也會影響激光脈沖壓力持續時間的變化。
　　關鍵詞：激光噴丸，高應變率，表面形貌，殘余應力，G-Z本構模型

　　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
　　聯系方式
　　王成：hpcwxg@zjut.edu.cn
 

責任編輯：趙澤南

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