中文摘要：

通过数值模拟和实验方法对U肋加劲板焊接残余应力进行了估算和分析，建立了三维热弹塑性有限元模型，采用生死单元法模拟焊缝填充和焊接热输入过程，实现了整个焊接过程中的动态应力和变形变化，得到了U肋加劲板的焊接温度场和应力场，分析了u肋加劲板的焊接残余应力分布，并与残余应力测试试验结果比较。结果显示：u肋加劲板近焊缝区残余拉应力达到材料屈服强度，母板远离焊缝区残余压应力平均值约为材料屈服强度的0．2倍，其分布趋势与实验测试得到的残余应力分布比较接近，证明了所采用的焊接数值模拟方法的正确性。

英文摘要：

In order to take into account the change of stress and deformation during the whole process of welding and the thermal field distribution of a U-rib stiffened plate, a thermal elastic-plastic FEM model was adopted and element birth and death was used to simulate the weld seam fill-in and heat input. And the residual stress distribution was investigated by numerical simulations and experiments. The comparison of numerical analyses and experimental results of distribution and magnitude of residual stress showed that residual stress near the weld seam is close to material yielding stress, the average value of the residual stress far from weld seam on the mother board was around 0.2 time of material yielding stress. The residual stress distribution tendency derived from numerical simulation was close to the experiment result, which proved the validity of the numerical simulation.