焊接接头力学不均匀体断裂力学参量的数值分析  

Numerical Analysis on Fracture Mechanics Parameters of Mechanical Heterogeneous Welded Joints

作　　者：沙鹏[1] 贺定勇[1] 田富强[1] 李晓延[1] 史耀武[1] 

机构地区：[1]北京工业大学材料科学与工程学院,北京100022

出　　处：《北京工业大学学报》2000年第z1期93-98,共6页Journal of Beijing University of Technology

基　　金：国家自然科学基金资助项目(59501011);北京市科技新星资助项目

摘　　要：应用ＭＡＲＣ有限元分析软件对平板拉伸和三点弯曲试样焊接接头力学不均匀体的断裂参量──Ｊ积分进行了数值分析．考察了焊接接头不均匀裂纹体Ｊ积分的守恒性，以及不同裂纹长度、强度匹配和焊缝宽度在加载过程中对Ｊ积分及塑性区发展规律的影响．结果表明：焊接接头Ｊ积分具有守恒性，裂纹越浅，加载时塑性区越大，断裂韧性值越高．高匹配焊缝中的裂纹更容易进入浅裂纹状态，从而使高匹配焊缝具有较好的抗断性能．焊接接头强度匹配因子Ｍ对Ｊ积分值有很大的影响．焊缝宽度对Ｊ积分值也有影响．An elastic-plastic finite element method and a virtual crack extension method have been utilized to simulate the J-integral in center-cracked panel (CCP) specimens and three-point bend (TPB) specimens by using MARC finite element program. The path independence of J-integral of welded joint has been investigated. The analysis is done on center-cracked panel specimens and three-point bend specimens with different crack length. strength matching and weld width. The effects of mechanical heterogeneity on plastic zones of welded joint have been investigated. The results show that for shallow crack, the plastic zone turns large in loading process, and the fracture toughness turns high. The plastic zone is more likely to occur with overmatched joint than with undermatched joint. and overmatched joint is more inclined to show the fracture behavior of shallow crack than undermatched joint Therefore, the fracture-resistant capability of overmatched weld is better than that of undermatched weld. The strength matching factor M is an important factor affecting the J-integral. The J-integral value is variable with the diversity of weld width.

关 键 词：焊接接头  J积分  有限元方法  力学不均匀 

分 类 号：TG407[金属学及工艺]