Strain measurement of polymer materials by digital image correlation combined with finite-element analysis

Digital image correlation (DIC) can provide deformation information of a specimen by processing its two digital images captured before and after the deformation. In this study, a DIC method based on a modified coarse–fine iterative method is combined with finiteelement analysis to obtain the strain and displacement data. This method is first verified with the use of an aluminum specimen under uniaxial testing. For polymer materials, polypropylene specimens with and without short glass fibers and polydimethylesiloxane specimens with and without dyes are tested. Results indicate that the present method can capture the strains of these specimens even under high elongation and without artificial speckle pattern on their surfaces. Thus, the mechanical behavior of polymer materials can be characterized and the effects of additional ingredients added to the materials can be assessed through the developed DIC method.