复合型裂纹断裂的新准则  

NEW FRACTURE CRITERION FOR MIXED MODE CRACKS

作　　者：任利[1] 朱哲明[1] 谢凌志[1] 张茹[2] 艾婷[2] 

机构地区：[1]能源工程安全与灾害力学教育部重点实验室,四川大学建筑与环境学院,成都610065 [2]四川大学水力学与山区河流开发保护国家重点实验室,水利水电学院,成都610065

出　　处：《固体力学学报》2013年第1期31-37,共7页Chinese Journal of Solid Mechanics

基　　金：国家重点基础研究发展规划(973)项目(2010CB732005,2011CB201201);国家自然科学基金项目(51074109)资助

摘　　要：以Ⅰ-Ⅱ复合型裂纹为研究对象,对裂纹尖端的塑性区分布规律进行了理论分析.引入两组评价裂纹尖端应力场对裂纹扩展影响的参数,考虑裂纹尖端存在的局部塑性变形,并采纳如下两个假设,(1)裂纹沿最短路径穿过塑性区向弹性区扩展,(2)当在扩展方向上的弹塑性边界极半径r大于其临界极半径rC时,裂纹开始扩展.在此基础上,导出了新的复合型裂纹断裂准则,并与现有部分断裂准则及实验结果进行了对比.结果表明:新建立的复合裂纹断裂准则与实验结果吻合程度非常高.文中还分析了裂纹尖端应力场对复合断裂的影响机制,阐述了以单一KⅠC或KⅡC建立的复合裂纹扩展准则的局限性以及考虑裂纹尖端应力场的必要性.For mixed mode I-II cracks, retically. Two groups of parameters, which the plastic zone distribution around crack tips is analyzed theocan be used to evaluate the effect of crack tip stress field on crack propagation, are introduced, with local plastic deformation being considered. In this study, we adopt the following two assumptions： （1） cracks propagate in the direction in which the plastic region boundary is the shortest to the crack tip, （2） once the radius from crack tip to the shortest plastic region boundary reaches the critical value,the crack starts to propagate. Based on these assumptions,a new fracture criterion for mixed-mode crack is developed. The comparisons with the existing fracture criterions and the experimental results show the present crack propagation criterion gives an agreement good prediction with the experiments. Moreover,the limitation of the existing single parameter （Kxc or KHc） criterion are present, and the effect of the crack tip stress field on the mixed-mode crack propagation is also discussed in detail.

关 键 词：复合裂纹 启裂角 断裂准则 临界半径 

分 类 号：O346.1[理学—固体力学]