A 2D mark shearing technique for characterizing the mechanical properties of material

The digital image correlation (DIC) method has been widely used in mechanical experiments due to their non-contact, full-field feature and high accuracy in displacement measurement. Yet the precision in strain determination is not so desirable. In this paper, a 2D mark shearing technique was proposed to improve the accuracy of the strain measurement in both vertical direction and horizontal direction. A four-prism system was designed and used to introduce a shearing distance of the marks, which were made on the specimen to calculate the two strain components. The measurement principle of the mark shearing technique is described in detail. A tensile experiment using an aluminum sample was conducted, and the Young's modulus and Poisson ratio were measured. The successful experimental results demonstrated the feasibility of this method.