基于裂纹扩展尺寸概率密度演化法的疲劳可靠性预测方法研究

STUDY ON FATIGUE RELIABILITY PREDICTION BASED ON CRACK PROPAGATION SIZE PROBABILITY DENSITY EVOLUTION METHOD

疲劳破坏是金属构件的一种主要破坏形式。该文提出一种新的疲劳可靠性预测方法—裂纹扩展尺寸概率密度演化法,该方法通过求解裂纹扩展尺寸时变概率密度函数来预测疲劳寿命可靠性。首先建立随机裂纹扩展模型,然后根据此模型建立概率密度演化方程,并运用数值方法进行求解。最后的算例证明了裂纹扩展尺寸的概率密度函数具有演化特征,新方法计算结果与蒙特卡罗法的结果符合较好。

Fatigue damage has been considered to be a primary failure mode for metal components. The present work proposes a new fatigue reliability prediction method, named Fatigue Crack Propagation Size Probability Density Evolution Method. The method focuses on a time-dependent fatigue size probability density function to predict fatigue reliability. A Stochastic crack propagation model is build, then the probability density evolution equation is set up based on the model to figure out crack propagation size probability density with a numerical method. The numerical example shows that the crack probability density function has evolution characteristics, the result from the proposed method is in an agreement with that from Monte-Carlo method.