Experimental study and numerical modeling of the stage of development of fractures in low-carbon steel

Abstract

This paper presents an experimental and numerical study of low-carbon steel under uniaxial tension to failure. The tensile test with destruction was carried out on an MI40 tensile testing machine. This machine allows you to test samples in tension and displays a curve of force versus elongation. Low-carbon steel cylindrical specimens are prepared according to ISO 6892–1:2019 and conform to Type II. To evaluate the test, the resulting averaged force-elongation curves were converted into engineering stress-strain curves. Engineering (technical) stress-strain curves are brought to truth. In the true diagram, the third stage - the development of the cervix - is assumed to be linear. Numerical studies were carried out using true tension diagrams. In the numerical study, all three stages of extension were simulated. The first stage is linear and is specified by Young’s modulus and Poisson’s ratio. From the total true deformation, the plastic one is extracted and applied in the second stage of deformation. The third stage is modeled by such parameters as a dependence of the degree of destruction on displacement, fracture strain, stress triaxiality and strain rate. Comparative graphs of the dependence of stress on deformation from experimental and numerical studies were obtained.