LOCAL COMPLIANCE EXPERIMENTS AND CRACK CLOSURE MODELS

The “plasticity-induced crack closure” phenomenon is the leading mechanism which controls the main effects on fatigue crack growth (e.g. stress ratio and load interaction effects) in metallic materials. Experimental tests are usually carried out to quantify the physical phenomenon, but some aspects concerning the elaboration of acquired signals are not yet clear. From the analytical point of view, the so-called Strip Yield model has proven to be the most versatile and powerful tool for estimating crack closure levels, but its application to steels is not yet straightforward. The present work tries to add some new ideas on the elaboration of local compliance experimental data in crack closure analysis simulating experimental P-offset loops by means of an optimised Strip Yield model implementation enriched by a novel and recently presented module based on the Westergaard’s elastic complex potentials. Analytical results gave the possibility to investigate some of the different parameters which influence local compliance measurements.