The experimental and theoretical study of plastic deformation in the fatigue crack tip based on method of digital image correlation

This work is devoted to the experimental study of strain distribution at crack tip using digital image correlation technique. The real strain fields were compared with an elastic solution for verification of a hypothesis about link of the elastic-plastic and elastic strain fields at crack tip using the coupling between Young's modulus and the secant plasticity modulus. The precracked plane specimens of titanium alloy VT1-0 with a thick of 1 mm were used in experimental program. The method of digital image correlation based on system StrainMaster was used for measurement the plastic deformation with spatial resolution up to 1 mkm The strain field was obtained for different crack length and different biaxial coefficient was obtained using biaxial testing machine Biss BI-00-502. Numerical simulation of deformation fields at the fatigue crack tip was done. A qualitative correspondence between the theoretical, calculation and experimental results has been shown. (C) 2018 The Authors. Published by Elsevier B.V.