变幅载荷下纤维金属层板的疲劳与寿命预测

Fatigue Life Prediction of Fiber Reinforced Metal Laminates Under Variable Amplitude Loading

文章建立了纤维金属层板等幅疲劳载荷下的疲劳裂纹扩展速率与寿命预测模型。在此基础上对玻璃纤维 -铝合金层板 (GLARE)的疲劳裂纹扩展与分层扩展行为进行了试验研究 ,探讨了层板过载疲劳行为的机理 ,提出了纤维金属层板变幅载荷下疲劳寿命预测的等效裂纹闭合模型 。

Fiber reinforced metal laminates (FRMLs), a new type of hybrid composites, are finding wide applications in the aerospace industry. The material is featured by its excellent fatigue performance and damage tolerance. Reliable life prediction methods are required for the successful application of this material. For this purpose, a mechanism\|based fatigue model was developed for the prediction of the fatigue lives of FRMLs under constant amplitude loading. The model was based on an analytical approach for the determination of the bridging stress over the crack faces by intact fibers. The fatigue behaviors of glass fiber reinforced laminates (GLARE), including crack growth and delamination, under constant amplitude loading following a single overload were investigated experimentally, and the mechanism of the effect of an overload on the crack growth rates was identified. An equivalent crack closure model for predicting crack growth in FRMLs under variable amplitude loading was presented. All the models in this paper were verified by applying to GLARE under constant amplitude loading and Mini\|TWIST load sequence. Good agreement was achieved. [