Monitoring Initiation and Growth of Crack in a Particulate Composite Material Using Nondestructive Testing Techniques
AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
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In recent years, a considerable amount of work has been done in studying damage characteristics in highly filled polymeric materials, using nondestructive testing techniques The importance of these studies stems from the fact the damage can significantly affect the constitutive and the crack growth behavior in these materials. Experimental findings reveal that damage, expressed in terms of the attenuation of the acoustic energy, increases with increasing strain rate and the critical damage is relatively insensitive to the strain rate. They also reveal that the damage state correlates well with the constitutive behavior of the material. In addition, for pre-cracked specimens, the damage state near the tip of a stationary crack is dependent on the loading history. In this study, the damage field near the crack tip in an edge-cracked sheet specimen subjected to a constant strain rate of 0.125 min-1 was investigated using the real-time x-ray technique.