力学学报 ›› 2017, Vol. 49 ›› Issue (6): 1312-1321.doi: 10.6052/0459-1879-17-209

• 固体力学 • 上一篇    下一篇

基于构型力断裂准则的裂纹与夹杂干涉问题

古斌, 郭宇立, 李群   

  1. 西安交通大学航天航空学院机械结构强度与振动国家重点实验室, 西安 710049
  • 收稿日期:2017-06-01 出版日期:2017-11-15 发布日期:2017-12-02
  • 作者简介:李群,副教授,博士生导师,主要从事断裂与损伤力学研究.E-mail:qunli@mail.xjtu.edu.cn
  • 基金资助:

    国家自然科学基金资助项目(11472205).

CRACK INTERACTING WITH AN INDIVIDUAL INCLUSION BY THE FRACTURE CRITERION OF CONFIGURATIONAL FORCE

Gu Bin, Guo Yuli, Li Qun   

  1. State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi'an Jiaotong University, Xi'an 710049, China
  • Received:2017-06-01 Online:2017-11-15 Published:2017-12-02

摘要:

基于构型力概念提出一种可判断裂纹起裂以及裂纹扩展方向的新断裂准则.该准则假设当构型合力值达到一个临界值时裂纹开始扩展,而裂纹扩展的方向则为构型合力的矢量方向.基于此断裂准则,本文开发构型力的有限元计算方法,实现对裂纹扩展的数值模拟,并着重对工程中常见的含孔洞/夹杂结构的裂纹扩展问题展开研究.研究结果表明,基于构型力的裂纹扩展准则可以很好地预测裂纹与孔/夹杂的干涉作用,其数值模拟结果与实验结果相符,从而验证了该裂纹扩展模拟方法的有效性.通过对裂纹和夹杂(圆孔、软夹杂、硬夹杂)干涉问题的数值模拟表明,裂纹前端夹杂对裂纹的扩展具有重要影响.裂纹的扩展方向与裂纹和夹杂的相对位置、以及夹杂类型密切相关.软夹杂和圆孔会吸引裂纹向其扩展,而硬夹杂会排斥裂纹扩展,裂纹在扩展过程中会绕开硬夹杂.当裂纹与夹杂夹角较小时,夹杂对裂纹扩展的影响作用明显,当夹角较大时,夹杂对裂纹扩展的影响较小;特别当裂纹与夹杂夹角为45°时,软夹杂和圆孔可能会抑制裂纹的扩展,使裂纹扩展发生止裂.研究结果有助于认清含孔洞/夹杂结构中的裂纹扩展或止裂问题,对于工程中的断裂问题具有重要指导意义.

关键词:

构型力|断裂准则|裂纹扩展|夹杂|孔洞

Abstract:

Based on the concept of configurational force, a new fracture criterion is proposed to determine the crack initiation and the direction of crack propagation. The criterion assumes that when the resultant configurational force reaches a critical value, the crack begins to grow, while the direction of the crack propagation is the vector direction of the resultant configurational force. Moreover, the finite element method of configurational force is developed to realize the numerical simulation of crack propagation. The crack propagation problem of the structure with an individual hole/inclusion in engineering is studied. The results show that the crack propagation criterion based on configurational force can predict the crack growth interacting with an individual hole/inclusion well, the results of the numerical simulation are consistent with experimental results, which verifies the validity of the simulation method of the crack propagation. The numerical simulation of the interference between cracks and inclusions (holes, soft inclusions or hard inclusions) shows that the inclusion near tip of the crack has an important influence on the propagation of the crack. The propagation direction of the crack is related to the relative position of crack and inclusion, and the type of inclusion. The soft inclusion and the circular hole attract the crack to expand, while the hard inclusion will repel the crack growth, and the crack will bypass the hard inclusion during the propagation. When the intersection angle of the crack and inclusion is small, the effect of inclusion on crack propagation is obvious. The inclusion has little effect on crack propagation when the angle is large. Particularly, when the angle is 45°, and the growth of soft inclusion may suppress the crack propagation. This study can help to understand the crack propagation in the structure with voids and inclusions, and have important guiding significance for the fracture problems in engineering.

Key words:

configurational force|fracture criterion|crack propagation|inclusion|hole

中图分类号: 

  • O346.1