Mesh sensitivity effects on fatigue crack growth by crack-tip blunting and re-sharpening

Crack-tip blunting under tensile loads and re-sharpening of the crack-tip during unloading is one of the basic mechanisms for fatigue crack growth in ductile metals. Based on an elastic-perfectly plastic material model, crack growth computations have been continued up to 700 full cycles by using remeshing at several stages of the plastic deformation, with studies of the effect of overloads or compressive underloads. Recent published analyses for the first two cycles have shown folding of the crack surface in compression, leading to something that looks like striations. The influence of mesh refinement is used to study the possibility of this type of behaviour within the present method. Even with much refined meshes no indication of crack surface folding is found here. (c) 2006 Elsevier Ltd. All rights reserved.