疲劳缺口系数评述

对疲劳缺口系数Ｋｆ的定义和影响因素进行了全面综述，对目前已被普遍接受和广泛使用的一些典型Ｋｆ表达式作了系统的回顾和评述。按照不同的Ｋｆ表达式建立所作的基本假设可将Ｋｆ表达式大致分为平均应力模型、断裂力学模型和场强法模型三类。对以上三类模型的比较分析表明，平均应力模型是应力场强法模型的特例；断裂力学模型是建立在非扩展小裂纹基础上的，对应力集中系数较大的缺口较为合理；应力场强法模型是一个比较有前途的模型。

Fatigue Notch Factor:A Review

Fatigue notch factor is a significant coefficient for fatigue notched strength predication. In this paper the definition and the primary influence of fatigue notch factor are discussed,and some expressions of fatigue notch factor which are recently and commonly used are briefly reviewed.According to their establishments,all the expressions of fatigue notch factor can be classified into three kinds of models:general average stress (AS)model, accepted fracture mechanics (FM) model, and promising stress field intensity (SFI)model. Analysis and comparison among the different models are made based on fatigue mechanism and experimental results. It is found that AS model is a special case of SFI model,FM model based on the no-propagation short crack is suited to the condition with higher stress concentration,and SFI model is the most reasonable and potential one with bright prospect.