FRACTURE SURFACE-ENERGY MEASUREMENT AT HIGH CRACK SPEED USING A STRIPSPECIMEN - APPLICATION TO RUBBER-TOUGHENED PMMA

An experimental procedure is proposed to measure the lowest elastic st ored energy density leading to a rapid crack propagation (RCP) in poly meric materials. A strip specimen with a blunt saw cut is uniformly lo aded and a razor is pushed into the saw cut to initiate the crack. The very high crack velocity which is reached is measured with a resistiv e coating on the sample surface. Results obtained for a rubber toughen ed PMMA show that fracture energy for RCP at approximately 500 m/s is much smaller than that in a quasi static tests. The material exhibits a ductile-brittle transition under particular loading conditions.