Tensile deformation behaviour of ferritic-pearlitic steel studied by digital image correlation method

Abstract

Tensile deformation behaviour of ferritic-pearlitic steel was studied by the digital image correlation (DIC) method. Room temperature tensile tests were carried out at an initial strain rate of 1 × 10–3 s–1 up to a defined elongation or fracture. The elongation and contraction were measured on the surface of cylindrical tensile specimens with random speckle pattern using stereo CCD camera system. The DIC elongation data were related to the data measured by an extensometer touching the specimens. The data from the DIC method were used for calculations of true stress-true strain tensile curves, strain hardening exponents and work hardening rates during uniform deformation up to the onset of plastic instability as well as non-uniform deformation during necking. Numerical simulations of strain fields within the gauge region of the specimens using finite element method were validated by the experimental data from the DIC method.