应力复合型裂纹焊接接头裂端场及其断裂参量分析  

Analysis of Crack-tip Stress Field and Fracture Parameter of Welded Joints Containing Mixed Cracks

作　　者：张敏[1] 付翀[2] 李继红[1] 李益民[3] 周荣灿[3] 

机构地区：[1]西安理工大学,西安710048 [2]西安工程大学,西安710048 [3]西安热工研究院,西安710032

出　　处：《机械科学与技术》2008年第1期106-110,共5页Mechanical Science and Technology for Aerospace Engineering

基　　金：教育部激光技术国家重点实验室高级访问学者基金项目(2000101);陕西省教育厅自然科学基金项目(05JK277)资助

摘　　要：针对含Ⅰ+Ⅱ应力复合型裂纹的焊接接头,应用弹塑性有限元方法分析了其裂端应力场的分布规律。并对不同组配焊接接头的裂纹张开位移(COD)断裂参量及其复合角进行了数值计算,讨论了加载角度和接头强度组配对焊接接头中应力复合型裂纹的断裂行为及其断裂参量的影响机制。研究结果表明,无论何种强度组配,焊接接头裂纹尖端应力场的分布是不对称的。裂端上部发生锐化现象,而裂端下部发生钝化现象。断裂参量COD值的大小受接头组配的影响,因此,不能简单地采用全母材的性能代替接头进行焊接接头的断裂分析。加载角度对焊接接头中复合型裂纹Ⅰ、Ⅱ型主导性存在很大的影响,而接头强度组配对其影响不明显;而裂纹复合角则会受到加载角度及材料组配因素的影响。因此,在进行含应力复合型裂纹的焊接接头的COD断裂参量的计算时,必须考虑这些因素的综合影响作用。The stress distribution of welded joint containing the mixed mode Ⅰ＋Ⅱ crack are analyzed by elastoplastic finite element method. The fracture parameter COD （crack opening displancement） and its mixity angles of mismatched welded joints are calculated, and the influences of the loading angles and strength matching on welded joint are analyzed. The simulated results show that there is asymmetry for the stress field of crack-tip of welded joint, and the upper crack-tip is sharpening, while the lower crack-tip is blunting. The fracture parameter COD changes with strength matching, thus base metal cannot be used to substitute the welded joints for simplification. The effect of loading angle on the domination of mode Ⅰ or Ⅱ of the mixed mode Ⅰ＋Ⅱ crack is evident, but the effect of strength matching is not obvious. The values of mixity angles depend on the loading angles and strength matching, respectively. Therefore, the above factors must be considered during the calculation of the fracture parameter COD of welded joint containing the mixed mode Ⅰ＋Ⅱ crack.

关 键 词：有限元方法 Ⅰ+Ⅱ复合型裂纹 焊接接头 加载角 

分 类 号：TG401[金属学及工艺—焊接]