Effect of remaining ligament on fatigue crack growth

Abstract

Fatigue crack growth (FCG) has been studied assuming that Keff is the crack driving force. However, the effect of crack ligament on FCG rate is not clear. Experimental-numerical work was developed in the 18Ni300 maraging steel considering different load blocks with the same initial K. No effect of crack ligament was observed experimentally, which was explained by the inexistence of crack closure effects. In the numerical work transient effects were observed for the plane stress state, which disappear for the plane strain state and some effect of crack ligament was found. In both cases this was attributed to crack closure phenomenon.