Automated fatigue crack growth analysis of components

AbstractA new methodology has been developed for automated fatigue crack growth (FCG) life analysis of components based on finite element (FE) stress models, weight function stress intensity factor (SIF) solutions, and algorithms to define idealized fracture geometry models. The idealized fracture geometry models are rectangular cross-sections with dimensions and orientation appropriate to an irregularly shaped component cross-section with arbitrary stress gradients on the crack plane. The fracture model geometry algorithms are robust enough to accommodate crack origins on the surface or in the interior of the component, as well as finite component dimensions, arbitrarily curved component surfaces, arbitrary stress gradients, and crack geometry transitions as the crack grows. Stress gradients are automatically extracted from multiple load steps in the FE models for input to the fracture models. The SIF solutions accommodate univariant and bivariant stress gradients and have been optimized for both computational efficiency and accuracy. The resulting calculations can be used to automatically construct FCG life contours for the component and to identify hot spots. Ultimately, the new algorithms will be used to support automated probabilistic assessments that calculate component reliability considering variability in the initial crack size, initial crack location, crack occurrence rate, applied stress magnitudes, material properties, inspection efficacy, and inspection time