Experimental studies on dynamic fracture behavior of thin plates with parallel single edge cracks

Dynamic fracture behavior of polymer PMMA thin plates with three- and four-parallel edge cracks was studied by means of the method of caustics in combination with a high-speed Schardin camera. A series of dynamic caustic patterns surrounding the crack tip and fracture path of the specimen were recorded simultaneously by two types of focused images. Some dynamic fracture parameters such as the dynamic stress intensity factor, crack velocity and acceleration were determined. The evolution of dynamic stress intensity factors on the parallel edge cracks, due to the dynamic unloading effect, was analyzed from the viewpoint of the release of elastic strain energy.