考虑层间应力的复合材料疲劳寿命预测方法

In response to the phenomenon that composite laminates are prone to delamination under fatigue load， often starting from the edge， analytical methods are used to solve the interlayer stress of composite laminates and obtain the distribution of interlayer stress at each interface under tensile and bending loads. The concept of local average stress was proposed to process the interlayer stress near the free boundary. The improved Hashin delamination failure criterion was used as the delamination criterion to select the local average stress between dangerous layers，which was introduced into the composite S-N curve model. The composite material life data under tensile and three-point bending fatigue loads were used for fitting， and the fitted model was used for life prediction. The results shows that the fitting accuracy is high，and the predicted life is within ±2 times the error band. The model was compared with three commonly used S-N curve models，and it was found that the overall prediction results of this model were the best，with the smallest prediction error for tensile and bending fatigue life.