New fatigue crack growth law for 316L stainless steel based on plastic CTOD.

Abstract

This thesis is concerned with a new low for describing the fatigue crack propagation on a 316L steel (austenitic stainless steel). A new methodology is presented based on the plastic contribution of the Crack-Tip Opening Displacement (CTODp). The CTODp is estimated from full-field displacement data measured with Digital Image Correlation (DIC). The protocol for post-processing the displacement information to generate the CTODp is described and applied to Compact Tension specimens at different fatigue stages. The new law correlates the fatigue crack propagation rate versus the CTODp in a linear fashion. The results are very promising given that this new methodology does not require small-scale yielding to hold, unlike when linear elastic fracture mechanics is employed.