摘要
在循环载荷下疲劳裂纹的裂纹形貌在稳定扩展区近似为半椭圆形状,因此通过Paris方法根据疲劳裂纹表面尖端点应力强度因子的变化幅值(△K)得到扩展速率与真实的裂纹速率会有误差。为了更好的研究疲劳裂纹的性质,本文通过分析紧凑拉伸(CT)试样的疲劳裂纹扩展后的三维形貌,采用Jiang-Sehitoglu循环塑性模型和疲劳准则以及Paris公式对裂纹扩展速率进行了有限元数值模拟,对扩展形貌的沿厚度方向裂纹的扩展速率进行了分析,发现在裂纹中间区域,疲劳裂纹扩展速率几乎相等。
The crack propagation shape under cyclic load is approximately semi-elliptical in fatigue stability extension. The Paris law leads to an error in prediction of fatigue crack growth rate if the range value of stress intensity factor(AK) of crack tip on the surface is used. In this paper, the shape of fatigue crack in compact tension(CT) specimens were analyzed. A cyclic plasticity model combined with the fatigue criterion that is presented by Jiang and Sehitoglu is implemented into the finite element elastic-plastic stress analysis for the simulations of crack growth rates. The crack profile in the direction of thickness were analyzed. It is concluded that fatigue crack rates in the middle of profile were almost identical.
出处
《计算力学学报》
EI
CAS
CSCD
北大核心
2011年第B04期33-36,48,共5页
Chinese Journal of Computational Mechanics
基金
国家自然科学基金(10772115
10932007)资助项目