复杂形状焊缝疲劳裂纹演变过程仿真  

Simulation of fatigue crack evolution process of complex shape welds

作　　者：叶凡 魏国前[1,2] 余茜[1] 李山山 YE Fan;WEI Guoqian;YU Xi;LI Shanshan(Key Laboratory of Metallurgical Equipment and Control Technology,Ministry of Education,Wuhan University of Science and Technology,Wuhan 430081,China;Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering,Wuhan University of Science and Technology,Wuhan 430081,China)

机构地区：[1]武汉科技大学冶金装备及其控制教育部重点实验室,湖北武汉430081 [2]武汉科技大学机械传动与制造工程湖北省重点实验室,湖北武汉430081

出　　处：《电焊机》2019年第9期103-109,共7页Electric Welding Machine

基　　金：国家自然科学基金项目(51575408)

摘　　要：针对实际工程运用中复杂形状焊缝疲劳裂纹扩展行为,基于Paris速率扩展模型,采用与积分路径无关的M积分计算裂纹前沿的应力强度因子,将裂纹前沿中间点应力强度因子作为裂纹扩展的控制参量,采取不同裂纹扩展方向准则,用半圆形描述焊趾初始表面裂纹,模拟了整个裂纹前沿在不同扩展阶段的动态演变过程。将疲劳裂纹扩展分为三个阶段,计算并比较了不同扩展阶段裂纹前沿应力强度因子KⅠ、KⅡ、KⅢ的分布及其变化规律,揭示了裂纹的载荷类型对疲劳裂纹扩展的影响,计算了不同扩展阶段疲劳寿命的占比。According to the fatigue crack propagation behavior of complex shape welds in actual engineering application and based on the Paris rate propagation model,the M-integral independent of the integral path is used to calculate the stress intensity factor of the crack front. And the stress intensity factor at the intermediate point of the crack front is used as the control parameter of crack propagation. Adopt different crack propagation direction criterion,and the initial surface crack of the weld toe is described by a semicircle. Simulate the dynamic evolution process of the entire crack front at different propagation stages. The fatigue crack growth is divided into three stages. The distribution and variation of stress intensity factors KⅠ,KⅡ and KⅢ of crack front in different propagation stages are calculated and compared. The influence of crack load type on fatigue crack growth is revealed,and the proportion of fatigue life in different expansion stages is calculated.

关 键 词：复杂形状焊缝 疲劳裂纹 演变 M积分 裂纹前沿 

分 类 号：TG405[金属学及工艺—焊接]