多点激光冲击强化表面粗糙度的有限元分析

Finite Element Analysis of Surface Roughness Generated by Multiple Laser Shock Peening

摘要:

激光冲击强化技术是一种新型的表面处理技术,它能够改善金属零件的疲劳性能,当考虑材料的抗疲劳性能时,表面粗糙度是一个关键参数。为了评估多点激光冲击强化表面粗糙度的变化规律,建立了三维有限元模型。采用一种改进的有限元分析方法获得零件表面节点的垂直位移,由数值模拟得到的离散化数据带入提出的表面粗糙度离散化公式,得到表面粗糙度Ra的值。数值模拟的结果与已有文献中的实验数据具有较好的一致性,验证了仿真模型的可行性。在此基础上,研究分析了搭接率、冲击次数和脉冲能量对表面粗糙度的响。

Abstract:

Laser shock peening (LSP) is a novel surface processing technique for improving the fatigue properties of metal parts, surface roughness is a critical parameter when fatigue strength resistance is concerned. In this paper, a three-dimensional (3D) finite element model was developed in order to assess the surface roughness evolution induced by multiple LSP. A modified finite element analysis (FEA) method was utilized to compute the vertical displacements profiles, discrete data obtained from the numerical simulations were subsequently input to the proposed discretized formula to calculate the surface roughness R_a. The results obtained from the numerical simulations were in good agreement with the experiment data from open literatures, which validates the proposed approach. After the validation of the numerical model, a parametric study was conducted in order to predict the effects of overlap rates, number of impacts, and pulse energy on surface roughness R_a.