预测疲劳裂纹扩展的多种理论模型研究

Various Theoretical Models Study of Prediction Fatigue Crack Growth

大多数工程断裂是因疲劳而引起的,所以金属材料的低周疲劳和裂纹扩展速率性能一直受到安全设计部门的关注。长久以来,国内外学者在建立金属材料低周疲劳行为和裂纹扩展速率性能之间的关系方面进行了多材料和多角度的研究。基于平面应力裂纹尖端小范围屈服应力应变场和疲劳裂纹扩展失效准则,提出用于I型疲劳裂纹扩展速率的预测模型。针对国内外相关工作的研究,基于平面应力裂纹尖端小范围屈服应力应变场和疲劳裂纹尖端循环塑性区内的应变能失效准则,提出一个可用于I型疲劳裂纹扩展速率的预测模型。借助已发表的15种金属材料对应的低周疲劳和裂纹扩展速率性能数据,详细分析和比较所提出的预测模型与其他6种预测模型的预测规律和结果。研究表明,所提出的预测模型能够预测更广泛的金属材料疲劳裂纹扩展速率,并且较其他6中预测模型更符合安全设计的理念。

Most engineering fracture is caused by fatigue, so the low cyclic fatigue and the crack growth properties are always concerned about the safety design department. For years, the relationship between the low cyclic fatigue and the fatigue crack growth is developed by domestic and foreign scholars from multi-material and multi-angle. A series of prediction models for mode-I fatigue crack growth are proposed with considering the small scale yield of plane stress crack tip condition and the failure criteria of fatigue crack tip. In present study, a prediction model for mode-I fatigue crack growth is proposed based on the small scale yield of plane stress crack tip and the strain energy failure criteria of cyclic plastic zone of fatigue crack tip. With the low cyclic fatigue and the fatigue crack growth for fifteen kinds of metals published in literatures, the proposed prediction model and the six kinds of prediction models are detailed analyzed and compared in the prediction law and results. Research shows that the proposed prediction model can be used to predict fatigue cracking for a wide range of metals and obey the safety design conception than other six kinds of prediction models.