Measuring crack growth and related opening and closing stresses using continuous potential drop recording

To improve resolution of in-situ measurement crack closure and opening in fatigue, potential drop (PD) technique has been further developed to measure thousands times through each load cycle with high precision. The results are interpreted physical phenomena like strain, Poisson’s effect, piezo-resistivity, plasticity, growth. Application the fatigue growth tests on aluminum 2024-T3 CCT specimens at different maximum stresses stress ratios, demonstrate that indeed variations PD can be associated development plasticity closure. Hence, allows timing magnitude experiments.