概率疲劳损伤力学的四参数Lognormal模型

FOUR-PARAMETER MODEL OF PFDM ON LOGNORMAL DISTRIBUTION

基于由宏观角度综合概率统计方法、疲劳研究及损伤力学三者建立的概率疲劳损伤力学PFDM(Probabilistic Flatigue Damage Mechanics)基本模型,考虑到工程中常用的Lognormal概率分布,经过大量的简化和推导,初步建立起适合于工程中常幅疲劳问题的Lognormal分布四参数PFDM模型,文中讨论了损伤参量D_(eq)、相对梯度RG的具体形式,在获取PFDM基本材料参数的前提下,可以对实际构件的疲劳寿命的Lognormal概率分布进行估算,文中还就40Cr调质钢、LY12CZ材料给出实例。

Based on PFDM (Probabilistic Fatigue Damage Mechanics) system established by combining statistic fatigue analysis and damage mechanics from the macroscope aspect, a simplified model (four-parameter model on Lognormal distribution) is proposed here in hopes of finding applications in engineering. If the materials constant concerned in the model are obtained by experiment, the propabilistic distribution of the (N) or log-life (t) of a component with original damage D0(x, y, z) could be predicted. The forms of damage parameter Deq and relative damage gradient RG0 in the model is discussed also. Some examples are given.