Author(s)

M.E. Biancolini, C. Brutti, G. Cappellini & M. D'Ulisse

Abstract

In this paper the crack growth emerging from a notch is studied for round bar under symmetric load condition. Modifying and synthesising some models found in literature, a method for fatigue life prediction is outlined and verified. The model takes into account the elastic-plastic crack growth and the change of crack shape during propagation. Overall life is divided in two parts: first a surface emerging crack propagates in the 3 D stressed region, then a Paris law stable propagation is assumed. A detailed 3D FEM model was developed in order to evaluate SIF vs. crack length, an elliptical crack shape was assumed imposing the proper eccentricity growth. The same FEM model was then exploited to evaluate the extension of plastic zone at notch tip. Fatigue life

Keywords