为了研究脉冲激光加热金属板的温度场和应力场的特点, 基于弹塑性力学理论, 采用有限元分析方法, 对脉冲激光扫描过程中金属板的温度场和应力场进行了3维数值模拟, 得到了温度场与应力场在时间和空间上的分布和变化规律。结果表明, 在脉冲激光扫描加热作用下, 金属表面发生多次熔化和凝固, 温度时间曲线呈锯齿形; 重熔区域应力场变化剧烈, 随间歇的激光脉冲发生强烈的拉-压应力波动; 金属基体冷却后在重熔区域留有高值残余拉应力, 纵向应力达799MPa, 横向应力达700MPa。

In order to study the thermal and stress field of metal plates irradiated moving pulsed laser beam, 3-D simulation models for thermal and stress field were built by means of finite element analysis method based on the thermal elasto-plastic constitutive theory. The distribution and evolvement of temperature and stress with the space and time was obtained. The numerical results show that the surface of the metal is melt within the laser pulse existing time, solidified in the interval of the discontinuous pulses. The temperature variation curves are serrate with different peaks. The stress field varies tempestuously with the tensile stress and compressive stresses transformed reciprocally. After the remelting and cooling down, residual tensile stress retains in the remelting zone with the longitudinal tensile stress reaches 799MPa and the transverse stress reaches 700MPa.