残余应力作用下的焊接接头疲劳裂纹扩展与寿命预测  

Fatigue Crack Propagation and Life Prediction of Welded Joints under Residual Stress

作　　者：张锦洲[1,2] 刘文家 姬世青 易先中[1] ZHANG Jin-zhou;LIU Wen-jia;JI Shi-qing;YI Xian-zhong(College of Mechanical Engineering,Yangtze University,Jingzhou 434023,China;MoE Key Laboratory of Metallurgical Equipment and Their Control,Wuhan University of Science and Technology,Wuhan 430081,China)

机构地区：[1]长江大学机械工程学院,荆州434023 [2]武汉科技大学,冶金装备及其控制教育部重点实验室,武汉430081

出　　处：《科学技术与工程》2024年第35期14976-14983,共8页Science Technology and Engineering

基　　金：国家自然科学基金(51974035,U1262108);油气藏地质及开发工程国家重点实验室(西南石油大学)开放基金(PLN2022-17);大学生创新创业项目(Yz2021117)。

摘　　要：为了探究焊接残余应力对不同初始角度疲劳裂纹扩展的影响,采用热弹塑性有限元方法计算焊接残余应力,结合线弹性力学和Paris公式计算应力强度因子和裂纹深度达到1 mm时的疲劳寿命和裂纹扩展速率。研究结果表明:随着裂纹初始角度增加初始应力强度因子不断减小,裂纹扩展过程中应力强度因子逐渐增大,然后保持稳定;初始角度为90°的裂纹的疲劳寿命最短,同时由于其表面长度较短,难以发现,需要特别警惕;裂纹深度达到临界尺寸时,初始角度为0°的裂纹扩展形态为椭圆形,随着初始角度的增加扩展形态向圆形过度;随着裂纹的扩展,焊接残余应力的影响不断减弱,不同初始角度裂纹的扩展速率的差别不断减小,最终趋于稳定;残余应力与外载荷共同作用会使裂纹扩展速率显著提高;结合计算结果给出了减少焊接残余应力提高疲劳寿命的工程建议,可以对压力容器等焊接结构件的设计提供有益的参考。In order to investigate the influence of welding residual stress on fatigue crack growth at different initial angles,the thermal elastic-plastic finite element method was used to calculate the welding residual stress,the stress intensity factor and the fatigue life and crack growth rate when the crack depth reached 1 mm were combined with the linear elasticity and Paris formula.The results show these as follows.The initial stress intensity factor decreases with the increase of the initial crack angle,and increases during the crack growth,and then remains stable.The fatigue life of the crack with the initial angle of 90°is the shortest,and special vigilance is needed because of its short surface length.When the crack depth reaches the critical size,the initial angle of 0°is elliptic,and with the increase of the initial angle,the crack propagation becomes circular.With the crack propagation,the influence of welding residual stress decreases and the difference of crack propagation rate at different initial angles decreases and then tends to be stable.The joint action of residual stress and external load can significantly increase the crack growth rate.At the same time,the engineering suggestions to reduce welding residual stress and improve fatigue life are given based on the calculation results,which can provide some reference for the design of welded structural parts such as pressure vessels.

关 键 词：焊接接头 数值模拟 应力强度因子 疲劳裂纹扩展 

分 类 号：TG445[金属学及工艺—焊接]