A 3D numerical study of ductile tearing and fatigue crack growth under nominal cyclic plasticity

Structures subjected to severe cyclic loading may fail due to low cycle fatigue. During the latter part of the fatigue life the crack growth rate may increase due to the occurence of crack growth from static failure modes, e.g. void growth. The present investigation attempts to predict the combined crack growth by means of nonlinear FE methods. The case studied is an axially loaded flat plate with embedded, nearly circular cracks growing under nominal cyclic plasticity, as test data for this case has been obtained previously. The fatigue part of the crack growth is determined by using the computed cyclic J-integral and the static mode crack growth from ductile tearing is determined from computations accounting for void nucleation/growth/coalescence by means of a modified Gurson-Tvergaard model. Comparison with the test results shows acceptable correspondence. © 1997 Elsevier Science Ltd.