焊接接头低周疲劳寿命估算方法的研究

The Investigation of an Approach to Low Cycle Fatigue Life Predictions of Welded Joints

将焊接接头的疲劳过程划分为疲劳裂纹形成和扩展两个阶段。基于均质缺口件的局部应力－应变法和线弹性断裂力学方法，通过考虑焊接过程中几何形状、残余应力和材料特性等因素的变化，建立了焊接接头低周疲劳寿命估算的一般技术流程。通过实例计算并与试验结果比较表明，本文提出的方法能够比较准确地预估低周疲劳失效焊接接头的疲劳寿命，因此，对于焊接结构的疲劳设计具有实际意义。

in this paper,the fatigue course of welded joints is divided into fatigue crackinitiation period and fatigue crack propagation period. Based on the local stress-strain methodof notched component with even property and line elastic fracture mechanics method,and bytaking into account the variabilities due to welding such as geometrical shapes, residualstresses and material properties etc., a general technical course adapting to predicting thelow cycle fatigue life of welded joints is establised. By predicting an example and comparingthe prediction results with test results,it is shown that the method proposed in this paper isfair well in predicting the fatigue life of welded joints under low cycle fatigue failure.Therefore, this method possesses practical significance for fatigue design of weldedstructures.