Abstract
A method for measuring the displacements and the strains near the interface of dissimilar materials is developed for studying the deformation behavior of composite materials under an impact load. In order to simplify the measurement, an inhomogeneous material composed of two dissimilar materials is used as a specimen. A split Hopkinson pressure bar apparatus is used to apply an impact load to the specimen. Several tests are performed with some combinations of the angle between the load and the interface. The consecutive images of the specimen surface are recorded with a high-speed camera. Mesh-based two-dimensional global digital image correlation is used for evaluating displacements and strains near the interface because local digital image correlation smooths out displacements and strains near an interface. Results show that the displacement and strain distributions associated with the difference of the wave speed between the dissimilar materials can be observed. Because of the difference of the rigidity, the shear strain concentration at the interface of the lower modulus side is observed. The proposed method can be used to reveal strain variation and distribution near the interface of dissimilar materials.
