A Software Tool for the Fatigue Growth Analysis of Multiple 3D Cracks from Fastener Holes

摘要

A software tool is developed to carry on automatic fatigue crack propagation analysis for the multiple three-dimensional (3D) cracks initiated from fastener holes. It is a computer code package being capable of handling the cases of multiple 3D cracks with quadratic curve fronts. The object-oriented programming language is used to develop user interfaces for the input of the initial data and output of the simulation results. To achieve life-span numerical simulation for the multiple 3D crack growth, ANSYS Parametric Design Language is used to create finite element model, conduct the stress analysis and regenerate finite element mesh for new crack configurations. Stress intensity factors of the cracks are determined using the crack opening displacements and incorporated into crack propagation laws to estimate the crack extension. An algorithm for the fast integration of crack growth equations is adopted to predict the fatigue crack growth life. As examples, two scenarios of corner cracks initiated from countersunk fastener hole in 2324-T39 alloy sheets are analyzed throughout their fatigue growth lives. The simulation results correlate well with the experimental ones.