疲劳门槛值统一理论模型的比较及验证  

Comparison and Verification of Unified Fatigue Threshold Models

作　　者：沈学成 黄毓晖[1] 朱明亮[1] 轩福贞[1] SHEN Xuecheng;HUANG Yuhui;ZHU Mingliang;XUAN Fuzhen(School of Mechanical and Power Engineering,East China University of Science and Technology,Shanghai 200237)

机构地区：[1]华东理工大学机械与动力工程学院,上海200237

出　　处：《机械工程学报》2020年第24期81-87,共7页Journal of Mechanical Engineering

基　　金：国家自然科学基金资助项目(51922041)。

摘　　要：针对应力比对疲劳裂纹扩展及门槛值的影响,依据裂纹闭合与裂纹扩展驱动力机制的统一思想,阐述了Zhu-Xuan模型与Kwofie-Zhu模型的建立过程,并基于25Cr2Ni2MoV转子钢焊接接头的疲劳裂纹扩展试验数据对模型进行验证。结果表明,两种模型在近门槛值区和Paris区均有良好的预测效果,其中Zhu-Xuan模型形式简单,对CrMoV钢具有普适性,预测门槛值的误差在10%以内,而Kwofie-Zhu模型预测结果更准确,但应用过程涉及参数求解,过程较复杂。研究认为,裂纹闭合与扩展驱动力机制的统一模型描述疲劳裂纹扩展行为的应力比相关性是合理可行的,且具有较好精度。Aiming at the effect of stress ratio on fatigue crack growth and fatigue threshold, the establishment process of Zhu-Xuan model and Kwofie-Zhu model are described, based on the unified thought of crack closure and crack propagation driving force mechanism, and the models are verified by using fatigue crack growth data of 25 Cr2 Ni2 MoV rotor steel welded joint. Results show that both the two models can well predict fatigue cracking in the near threshold and Paris regimes. The Zhu-Xuan model has a simpler form and is universal for CrMoV steel with an error of fatigue threshold prediction below 10%, while the prediction by the Kwofie-Zhu model is more accurate, and the application involves parameter solving, and is thus more complicated. It is demonstrated that the unified mechanistic modeling of crack closure and crack growth driving force to describe stress ratio dependence of fatigue crack growth behavior is reasonable and feasible with good accuracy.

关 键 词：疲劳裂纹扩展 应力比 疲劳门槛值 裂纹闭合 裂纹扩展驱动力 

分 类 号：TG115[金属学及工艺—物理冶金]