Measurement of the dynamic fracture toughness of polymethylmethacrylate by high-speed photography

摘要: Abstract The dynamic stress-intensity factor about the tip of a rapidly moving crack ( K D ) in polymethylmethacrylate (PMMA) has been measured, using ultra-high speed photographic techniques to record photoelastic patterns produced around tip. From same photographs, velocity cracks was determined. A gross roughening fracture surface found appear at speeds 1,300 ft sec−1 (396 m sec−1). geometry markings associated with roughening, value Young's Modulus for PMMA obtained over range 1,300–2,300 (400–700 These values were used interpret variation stress intensity factor, , velocity, and its relation morphology.