A method is developed for the direct measurement of the dynamic fracture toughness and the crack-growth speed in miniature samples. Using UCSD's recovery tension Hopkinson technique and high-speed photography, the miniature samples are dynamically loaded and the processes of crack initiation, crack growth, and crack arrest are captured. The recovery Hopkinson technique provides the capability to subject a sample to a single tension stress-pulse with a predefined time-resolved profile by trappingboth the reflected and transmitted pulses once the sample is loaded. Furthermore, the total energy of the pulse is controlled such that the crack extension is fully controlled. The technique is described and some preliminary results are presented.
展开▼
