Stress wave attenuation in shock-damaged rock
- Creators
- Liu, Cangli
- Ahrens, Thomas J.
Abstract
The velocity and attenuation of ultrasonic stress waves in gabbroic rock samples (San Marcos, California) subjected to shock loading in the 2 GPa range were studied. Prom P wave velocity measurements we determined the damage parameter D_p and crack density ε of the samples and related these to the attenuation coefficient (quality factor) under dynamic strains of 2×10^(−7) and at a frequency of 2 MHz using the ultrasonic pulse-echo method. A fit to the data yields the P wave spatial attenuation coefficient at a frequency of 2 MHz, α_p(D_p) = 1.1 + 28.2D_P (decibels per centimeter). From the relation between the attenuation coefficient and quality factor, the quality factor Q is given by Q^(−1) = 0.011(1 + 25.6D_p)(1 − Dp)^½. Using O'Connell-Budiansky theory relating crack density to velocity, the parameter in Walsh's theory was determined based on experimental data. An approximate method is also proposed to estimate the average half-length of cracks based on the attenuation measurements.
Additional Information
© 1997 by the American Geophysical Union. Paper number 96JB03891. Received January 3, 1996; revised December 10, 1996; accepted December 11, 1996. We thank T. Duffy, T. Mukerji, and D. R. Schmitt for numerous suggestions that improved the manuscript, and we thank G. Ravichandran for the use of the ultrasonic apparatus. This research was supported by NASA under NAGW-1941 and Air Force Technical Application Center, Contr. F19628-95-c-0115. Contribution 5631, Division of Geological and Planetary Sciences, California Institute of Technology.Attached Files
Published - jgrb10940.pdf
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Additional details
- Eprint ID
- 50806
- Resolver ID
- CaltechAUTHORS:20141024-142109125
- NASA
- NAGW-1941
- Air Force Office of Scientific Research (AFOSR)
- F19628-95-C-0115
- Created
-
2014-10-24Created from EPrint's datestamp field
- Updated
-
2021-11-10Created from EPrint's last_modified field
- Other Numbering System Name
- Caltech Division of Geological and Planetary Sciences
- Other Numbering System Identifier
- 5631