Experimental study of dynamic fracture behavior of PMMA with overlapping offset-parallel cracks

Dynamic fracture behavior of thin PMMA sheet with two overlapping offset-parallel cracks under tensile loading are investigated using the optical method of caustics in combination with a Cranz–Schardin high-speed camera. Both the dynamic caustic pattern of the crack tip and the trajectory of the crack propagation are recorded simultaneously. The initiation and propagation behavior of both edge cracks are observed. Some important dynamic fracture parameters such as the crack length, the crack velocity and acceleration as well as the dynamic stress intensity factors at the crack tip are extracted and their correlations are analyzed.