Digital Image Correlation Analysis and Numerical Simulation of Aluminum Alloys under Quasi-static Tension after Necking Using the Bridgman’s Correction Method

Quasi-static tensile test is a common, yet fundamental, experiment in determining the mechanical properties of materials. Often, the determination of the equivalent stress–strain relation is complicated by strain localization and necking in the tensile specimen, which results in a triaxial stress state in the specimen and invalidates the assumption of uniaxial tension. In this paper, a three-dimensional full-field Digital Image Correction (DIC) technique is used to obtain all the necessary geometric properties of a cylindrical tensile specimen during necking that are required in determining the Bridgman’s correction method to the true stress–strain relation. Finite element modeling is used to test the applicability of Bridgman’s correction method on three different aluminum alloys to quantify the effect of strain hardening on the triaxiality in the necked region.