高强钢激光熔透焊接接头残余应力数值分析

Numerical analysis of residual stress in high-strength steel laser penetration welded joints

为探究高强钢大功率激光单道熔透焊接接头中的残余应力及塑性应变分布规律,基于峰值指数递增双锥体热源模型对焊接接头进行热-弹-塑性有限元分析,发现采用该热源模型仿真计算的温度场与实际焊缝轮廓吻合较好,关键参数对比最大误差为-3.45%;焊接接头残余应力沿着焊缝中心至两边呈对称分布,沿路径L2在起焊与止焊处的应力分布波动较大,这与节点温度历程曲线相一致;焊接接头在焊缝区发生了塑性应变,而远离焊缝区范围内未发生塑性应变。沿路径L1的焊缝区最大塑性应变峰值及峰值梯度均为等效塑性应变;沿路径L2在起焊及止焊处的纵向、横向及等效塑性应变波动幅值较大,且等效塑性应变峰值最高,横向塑性应变峰值梯度最大,它们的值分别为0.064及0.079。

To investigate the distribution of residual stress and plastic strain in high-power laser single-pass full penetration welding joints of high-strength steel,the thermo-elastoplastic finite element analysis of laser penetration welding joint of high-strength steel was conducted based on the peak index increasing double cone heat source model.It was found that the temperature field simulated using this heat source model matched well with the actual weld profile,and the maximum error in comparing key parameters was-3.45%.The residual stress of the welded joint were symmetrically distributed from the center to both sides of the weld seam.The stress distribution at the starting and ending points along path L2fluctuates greatly,which was consistent with the node temperature history curve.The welded joint was subjected to plastic strain in the weld,but no plastic strain occurred in the range far from the weld.The maximum plastic strain peak and peak gradient in the weld along path L1 were equivalent plastic strains.The longitudinal,transverse,and equivalent plastic strain fluctuations at the starting and ending points along path L2 were relatively large.Moreover,the peak value of equivalent plastic strain was the highest,and the gradient of the peak value of transverse plastic strain was the highest,with values of0.064 and 0.079,respectively.