A DIC-based Taylor impact test by measuring inertia force from acceleration distribution to obtain uniaxial stress–strain behavior of pure aluminum

Abstract

The digital image correlation (DIC) technique is widely used to capture several kinematical quantities fields including displacement, velocity, strain, strain rate and acceleration in various kinds of the mechanical tests with the deformation of specimen. Considering the nature of nonuniform deformation in Taylor impact test, except the mentioned fields, the axial stress distribution is also required to evaluate the deformation behavior of materials. Recently, a measurement method for axial stress distribution is proposed based on an assumption of bilinear internal force distribution in specimen. However, the measured result only gives an approximate result. Besides, because the satisfaction of the assumption limits to several conditions, only the result obtained at a particular moment and position region is reliable. On the other hand, it is possible to calculate the axial stress distribution from the momentum balance law to avoid the mentioned assumption if the axial acceleration distribution is captured by the DIC technique. Unfortunately, the feasibility and accuracy for the method has not been discussed yet, even though some challenges on introducing DIC technique to Taylor impact test has already been done. Here, a method based on momentum balance law and axial acceleration distribution is newly proposed to obtain the axial stress distribution. The stress–strain curve in Taylor impact test is obtained by a simultaneously spatial combination between the stress and strain distributions. Then, the feasibility of the proposed method is discussed computationally and experimentally.