Numerical simulation method for fatigue crack propagation of maritime work pipe containing surface cracks

The invention discloses a numerical simulation method for fatigue crack propagation of a maritime work pipe containing surface cracks. The method comprises the following steps: step 1, establishing a pipeline welding numerical simulation model; 2, calculating a welding temperature field and solving a residual stress field in a crack-free state; 3, establishing a crack propagation model; 4, mapping of a welding residual stress field is completed; and 5, calculating the fatigue extension life. According to the method, the finite element method is adopted for conducting numerical analysis on the pipeline welding process, the residual stress field in the crack-free state is obtained, the welding residual stress is guided into the fatigue crack propagation model, and the fatigue life of the pipeline under the combined action of the residual stress and the alternating load is accurately predicted. 本发明公开了一种含表面裂纹海工管疲劳裂纹扩展的数值模拟方法，包括以下步骤：步骤1、建立管道焊接数值模拟模型；步骤2、计算焊接温度场及求无裂纹状态的残余应力场；步骤3、建立裂纹扩展模型；步骤4、完成焊接残余应力场的映射；步骤5、计算疲劳扩展