Crack growth in a new nickel-based superalloy at elevated temperature - Part II - Finite element analysis of crack growth

Crack growth at elevated temperature has been simulated using the finite element method for sustained and cyclic loading conditions, representative of time-dependent and time-independent crack growth. Elastic-creep (EC) and elastic-plastic-creep (EPC) models have been used to simulate the crack growth under sustained loads at 650 and 725 degrees C. Crack mouth opening displacements as well as the evolution of the inelastic zones due to creep and plasticity have been obtained. Elastic-plastic finite element analysis has been carried out to simulate the crack growth under cyclic load using a constitutive model. Fatigue crack growth was simulated for plane stress, plane strain and generalized plane strain loading conditions. The influence of plasticity on the effective crack driving force was also examined. Creep damage was found to be very limited at both temperatures for this alloy. Plasticity-induced crack closure was found to be absent in plane strain or generalized plane strain conditions, overestimated in plane stress loading conditions by the conventional compliance method. (C) 2005 Springer Science + Business Media, Inc.