One- and three-dimensional impact-induced tensional failure in rockPlanar impact (10 to 25 m/sec) experiments were employed to induce dynamic tensile failure in Bedford limestone for stress durations of 0.5 and 1.3 microsec. Ultrasonic P- and S-wave velocities of recovered targets demonstrate deficits caused by microcracks at tensile stresses greater than 35 and 60 MPa in 1.3 and 0.5 microsec experiments. Three-dimensional impact experiments on 20 cm-sized blocks of Bedford limestone and San Marcos gabbro demonstrate compressional wave velocity deficits up to 30 percent in the vicinity of the crater. The damage microcrack decreases as r exp -1.56 from the crater, indicating a dependence on the magnitude and duration of the tensile hoop stresses associated with the impact-induced shock wave.
Document ID
19920061914
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Ahrens, Thomas J. (NASA Headquarters Washington, DC United States)
Rubin, Allan M. (California Institute of Technology Pasadena, United States)