Boundary element analysis of fatigue crack propagation micromechanisms in austempered ductile iron

The Dual Boundary Element Method (DBEM) is used in this work to model the m icro mechanics of fatigue crack propagation in austempered ductile iron (AD I). Emphasis is put in devising accurate procedures fbr the evaluation of t he interaction effects between very close crack-microcrack arrays. Fracture parameters are computed via the so-called one-point displacement formula u sing special crack-tip elements. Crack propagation is modelled using an inc remental crack extension analysis; with crack extensions calculated using a propagation law that accounts for the near-threshold regime. Obtained resu lts are in agreement with experimental observations, providing evidence to fracture mechanics models proposed in the literature. (C) 2001 Elsevier Sci ence Ltd. All rights reserved.