确定总应变寿命方程参数的一种方法

为了使总应变寿命方程能够在较大寿命范围内具有理想的预测精度且其参数物理意义明确,基于总应变寿命方程中疲劳强度系数与疲劳延性系数的物理意义,建立了总应变寿命方程参数与单调拉伸强度极限和断面收缩率之间的关系,并结合TC4,GH4169及GH901合金的单调拉伸及疲劳试验数据,对其各自的总应变寿命方程参数进行了拟合,进而开展了疲劳寿命预测.结果表明:采用该方法确定的总应变寿命方程参数具有明确的物理意义,且对TC4,GH4169及GH901合金的疲劳寿命预测结果较为理想,其分散带基本在2倍以内. 

A method for determination of parameters in total strain life equation

In order to improve the prediction precision of total strain life equation in a wide range of fatigue life with the equation parameters having definite physical significance, the relationship among parameters of total strain life equation, monotonic ultimate tensile stress and percentage reduction of area was established based on the physical significance of the fatigue strength coefficient and the fatigue ductility coefficient of total strain life equation. Parameters in the total strain life equation for TC4, GH4169 and GH901 alloy were fitted and fatigue life predictions were carried out combining with monotonic tensile and fatigue test data. The results show that fatigue life predictions using the total strain life equation with the parameters fitted by the developed approach give better estimation within a scatter band of about two for TC4, GH4169 and GH901 alloy.