Development of the Method of Crack Growth Analysis and Its Applications

裂纹扩展分析方法的发展及其应用

基本信息

批准号：
12650104
负责人：
NISITANI Hironobu
金额：
$ 2.3万
依托单位：
Kyushu Sangyo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

A typical fracture of machines and structures is preceded by a propagation and coalescence of minute cracks that exist inside the body in advance or outbreak during life time. Therefore, in the prediction of the behavior of fracture, it is important to grasp a path of crack propagation and how to coalesce themselves during growth under given loading conditions.In order to realize an ideal simulation of crack propagation, the following two conditions are essential. The first is to use an adequate numerical scheme which can calculate the singular stress fields at the tip of an arbitrary shaped crack as accurately and effectively as possible.The second is to choose an adequate criterion that predicts the direction of crack propagation. In a conventional analysis, a maximum principle stress criterion or a local symmetry criterion is employed usually. The farmer enables relatively high-efficiency prediction but sometimes leads poor numerical results. On the other hand, the latter is reliabl … More e but too expensive to apply the crack propagation simulation among multiple cracks.In order to overcome the first condition, the Body Force Method, known as a powerful numerical method especially for crack problems is employed. The developed system can treat all two-dimensional crack problems essentially even in a case for extremely complex crack geometry where a number of branches and kink points are involved. In order to overcome the second condition, new prediction scheme for the direction of further crack propagation using a resultant force at the crack tip field is proposed. Through the numerical tests for many kinds of crack propagation problems, it was verified that the proposed criterion is much effective and provides highly accurate solution than ordinary methods.The developed crack propagation analysis system was applied many kinds of problems such as the crack propagation in a standard specimens, crack coalescence problem in a rectangular plates and failure simulation among multiple cracks in brittle materials under compressive stress. Less

机器和结构的典型断裂是在生命时期内存在的微小裂缝的传播和裂缝。如何在生长状态下结合自己。在两个条件下，首先要使用一个适当的数值方案CK的传播。在克服第一个条件的过程中，裂纹的传播模拟在克服第一个情况下，被称为裂纹问题的人体力量法可以治疗所有二维裂纹问题，以期为复杂的裂纹裂纹，其中许多分支和扭结点是第二个条件，通过在许多类型的裂纹传播问题的情况下，提出了在裂纹尖端领域进行进一步裂纹的方案。在标准标本中，CRITION非常有效，并且提供了高度准确的溶液，在矩形板中的裂纹合并和脆性材料中的多个裂纹中的家族鸡巴模拟