Coupled FEM-DBEM Simulation of 3D Crack Growth under Fatigue Load Spectrum

摘要

Numerical predictions of fatigue crack growth under load spectrum are obtained by coupled FEM-DBEM approach. An initial\udpart-through corner crack, in a pre-notched specimen undergoing a traction fatigue load, propagates becoming through the\udthickness. A two parameter crack growth law (“Unified Approach”) is calibrated by in house made constant amplitude\udexperimental tests and the crack growth retardation after an overload application is reproduced. The residual stresses responsible\udfor such retardation are calculated by a sequence of elastic-plastic static FEM analysis; such stresses are then applied to the crack\udfaces for the propagation simulation in a DBEM environment. A satisfactory agreement between numerical and experimental\udcrack growth rates are displayed, for both part-through crack and through the thickness crack. This approach provide general\udmodeling capabilities, with allowance for general crack front shape and fully automatic propagation.