Digital image correlation for mechanical behavior of viscoelastic materials

A digital image correlation system, which is a combination of a long-focus microscope and a digital image-measuring device, is developed for studying the mechanical behavior of the viscoelastic materials. In this paper, the precision of the digital image correlation system is assessed by using an extra solution within of the framework of infinitesimal strain in particular, the choice of the size of subset in the correlation technique is discussed when the displacements are not infinitesimal. Then, the system is employed to obtain the displacement field in each step, strain field in the interest area of the specimen, and the experimental results show that digital image correlation system can perform the precise measurements of the mechanical behavior of viscoelastic materials.