Digital Image Correlation for Experimental Characterization of Mechanical Properties

The aim of this study is to experimentally characterize the mechanical properties needed in numerical sheet forming simulation to describe the behavior of Laminated AA1050H24 aluminum alloy sheet. For this purpose, uniaxial tensile tests in three directions relative to the rolling direction (RD) were carried out with a universal testing machine, where the 45° orientation is the diagonal direction (DD) and the 90° orientation is the transverse direction (DT). The true stress and the true strain curves of the aluminum alloy sheet obtained from the tensile test are plotted for each direction. To assess the anisotropic properties of the sheet, the digital image correlation (DIC) technique is used to calculate longitudinal and transverse plastic strains (ε <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf> , ε <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</inf> ) by observing digital image correlation of specimens during uniaxial tensile testing. To define the deformation in the sheet thickness direction ability against the deformation in sheet plane deformation, the r value of the Lankford coefficient was calculated for each direction. According to the values of the Lankford coefficient obtained from the DIC observation, the studied material has a significant anisotropy. As a result of these experimental tests, the parameters of Swift's hardening law and the anisotropy coefficients of Hill's plasticity criterion, which are used as input data in the numerical simulation software (ABAQUS), are determined.