Probability Analysis of Widespread Fatigue Damage in LY12-CZ Aluminum Alloy Single-Row Seven-Hole Plate

In order to determine the average behavior time of widespread fatigue damage (WFD) in an aircraft multi-site damage (MSD) structure and complete the fatigue analysis of WFD sensitive parts, this paper adopts a probabilistic method to analyze the crack initiation and crack propagation of a single row of collinear seven-hole plates. The simulation analysis of the whole process from crack initiation to structural failure is realized. First, through statistical analysis of the test data of the LY12-CZ alloy single-detail plate with hole, the probability distribution of crack initiation life and growth rate is obtained, and this probability distribution is expressed by the randomization of variables. Then, using the related theories of fracture mechanics and fatigue statistics, the whole process of initiation, propagation, and connection of multiple cracks in the MSD structure to the occurrence of WFD was realized through the Monte Carlo method. Finally, a group of single-row seven-hole plate examples are used to verify the accuracy of the calculation results. The results show that the calculated results in this paper are in good agreement with the experimental data, and can accurately predict the life of MSD structures under a certain reliability.