Application of Digital Image Correlation Method in the Study of Deformation of Notched Carbon Steel Plates and Finite Element Simulation

This study aims to clarify the notch factor effect on the mechanical properties of carbon steel plates and the strain field distribution at the notch during the tensile process. To this end, tensile tests were conducted on 20, 45, and 60 steel notched plates of different sizes at 4 mm/min tensile speed, and the Johnson-Cook intrinsic structure model was used to calibrate the true stress-true strain relationship. The nodal strain and surface strain field distribution at notches were determined based on the digital image correlation (DIC) method, and the tensile process of 45 steel plates was simulated by Abaqus finite element method based on Johnson-Cook model to verify its accuracy. The deformation results of the three materials conformed to the Johnson-Cook model stress-strain law; the notch sensitivity of the materials increased and then decreased with the notch size, reaching the maximum at P = 0.2 mm. The DIC method results agreed well with the simulated strains, mainly concentrated near the root of the notch in the x-and y-axis directions. The strains in the xy-plane direction are roughly symmetrically distributed in a 45 degrees shear shape and mainly concentrated at the edge of the notch.