光子学报, 2015, 44 (4): 0414002, 网络出版: 2015-04-28
飞秒激光冲击AZ31B镁合金过程的数值模拟
Numerical Simulation of AZ31B Magnesium Alloy Shocked with Femtosecond Laser
激光技术 飞秒激光 有限元分析 镁合金 特征量 板材成形 Laser technique Femtosecond laser Finite element method Magnesium alloy Characteristics Sheet forming
摘要
采用有限元分析法对飞秒激光冲击AZ31B镁合金进行数值模拟, 研究了激光冲击处理对镁合金变形过程的影响, 分析了单脉冲激光冲击下材料内部的位移、动能、应力和应变的分布情况, 得到了材料的瞬态速度和应变率变化过程.仿真结果表明, 单脉冲飞秒激光冲击镁合金产生的塑性变形, 可在材料表面形成微米级凹坑, 中心点处最大位移为34 μm, 最大变形速度390 m/s; 在冲击初期, 材料表面的应力和应变主要分布在冲击区域中心节点和边缘附近, 并且得到镁合金的最大应力和最大应变率分别为955 MPa和1.8×106 s-1.研究结果能够为深入分析飞秒激光与镁合金作用时材料变形参量的变化规律提供数值理论依据.
Abstract
The laser shocking processing of AZ31B magnesium alloy sheet by the femtosecond laser pulse is numerically simulated with the finite element method. In the simulation, the effect of laser shock processing on the deformation process of AZ31B magnesium alloy is studied, the distributions of characteristics within the material, such as displacement, stress and strain, are analyzed, and the dynamic variation process of velocity and strain rate is discussed. The results indicate that the plastic deformation of magnesium alloy sheet shocked by single femtosecond laser pulse led to a micrometer-scale pit on the material surface. The maximum displacement at the center of the pit is 34 μm. And the maximum speed reaches 390m/s. Stress and strain of material aremainly distributed near the central dot and the edge of laser shocked region. The maximum stress of the central dot is 955 MPa, and the maximum strain rate reaches 1.8×106 s-1.The results show that the numerical simulation of the laser shocking processing of AZ31B magnesium alloy sheet by the femtosecond laser pulse is able to provide the numerical references for analysis of the variation laws of materials by femtosecond laser loading.
姚红兵, 于文龙, 杨昭, 李强, 高原, 李亚茹, 倪文强. 飞秒激光冲击AZ31B镁合金过程的数值模拟[J]. 光子学报, 2015, 44(4): 0414002. YAO Hong-bing, YU Wen-long, YANG Zhao, LI Qiang, GAO Yuan, LI Ya-ru, NI Wen-qiang. Numerical Simulation of AZ31B Magnesium Alloy Shocked with Femtosecond Laser[J]. ACTA PHOTONICA SINICA, 2015, 44(4): 0414002.