GRAPHICAL REPRESENTATION OF UNIAXIAL TENSILE TEST THROUGH DIGITAL IMAGE CORRELATION
Keywords:
Tensile test, Tensile properties, Digital image correlation, Ncorr, Strain fieldsAbstract
Digital Image Correlation (DIC) is a non-contact measurement method that identifies surface changes on a specimen by analyzing a sequence of photographs taken before, during, and after the loading process. DIC determines contour deformation, strain, and stress values by examining variations in the speckled pattern created by the random addition of black dots. In this research, DIC was used to visualize the graphical presentation of a uniaxial tensile test. To obtain stress and strain values, the study employed two methods: the conventional experimental uniaxial tensile test and the DIC method. Tensile steel specimens with five different thicknesses, ranging from 6 mm to 16 mm, were fabricated and tested. The specimens were cut at a 15-degree angle from the rolling direction from the same plate sheet for each thickness. It was discovered that the orientation of the applied forces can affect the changes in Young's modulus values, which are higher when the load is applied parallel to the direction rather than perpendicular to it. The open-source image correlation software package Ncorr, integrated with MATLAB, was used for DIC analysis. The results showed that both methods provided close values for tensile strength and Young’s modulus. The DIC method produced slightly lower values than the conventional technique but was still considered accurate for predicting tensile properties. The DIC models also demonstrated good agreement with the experimental findings, suggesting its suitability as a straightforward evaluation method for predicting tensile properties.