一种基于能量参数的非局部缺口疲劳寿命预测方法

Non-Local Method for Notched Fatigue Life Estimation Based on Energy Parameter

为了考虑应力集中对构件疲劳寿命的影响,采用能量参数作为疲劳损伤评估参量,发展了一种基于能量的非局部缺口疲劳寿命预测方法,该方法通过相同寿命条件下缺口试样与光滑试样的疲劳损伤等效关系确定用于定义缺口试样非局部临界体积的能量参数门槛值,并建立了能量参数门槛值与疲劳寿命的关系,进而通过迭代程序便可进行缺口试样寿命预测。试验验证结果表明:缺口试样能量参数门槛值与疲劳寿命在双对数坐标系下呈线性关系;所发展的方法对缺口疲劳试验试样的寿命预测精度较高,预测寿命分散带在2倍以内。

In order to take account of the effects of stress concentration on the fatigue life,non-local method for notched fatigue life estimation based on energy parameter,in which energy parameter has been used to evaluate fatigue damage,was developed.The energy parameter threshold value used to define non-local critical volume was determined based on the equivalent relationship of fatigue damage of a smooth specimen and a notched specimen under the same fatigue life condition.The relationship between energy parameter threshold value and fatigue life was established.Furthermore,the fatigue life of notched specimens could be calculated by recursive procedure.The results based on fatigue experiments of smooth and notched specimens show that：it presents a linear relationship between energy parameter threshold value and fatigue life in double logarithmic scale,and the fatigue life prediction of notched specimens give good estimation with a scatter band of less than 2.