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Dynamic tensile-failure-induced velocity deficits in rock

Rubin, Allan M. and Ahrens, Thomas J. (1991) Dynamic tensile-failure-induced velocity deficits in rock. Geophysical Research Letters, 18 (2). pp. 219-222. ISSN 0094-8276. https://resolver.caltech.edu/CaltechAUTHORS:20141023-090958603

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Abstract

Planar impact experiments were employed to induce dynamic tensile failure in Bedford limestone. Rock discs were impacted with aluminum and polymethyl methacralate (PMMA) flyer plates at velocities of 10 to 25 m/s. Tensile stress magnitudes and duration were chosen so as to induce a range of microcrack growth insufficient to cause complete spalling of the samples. Ultrasonic P- and S-wave velocities of recovered targets were compared to the velocities prior to impact. Velocity reduction, and by inference microcrack production, occurred in samples subjected to stresses above 35 MPa in the 1.3 μs PMMA experiments and 60 MPa in the 0.5 μs aluminum experiments. Using a simple model for the time-dependent stress-intensity factor at the tips of existing flaws, apparent fracture toughnesses of 2.4 and 2.5 MPa m^(½) are computed for the 1.3 and 0.5 μs experiments. These are a factor of ∼ 2 to 3 greater than quasi-static values. The greater dynamic fracture toughness observed may result from microcrack interaction during tensile failure. Data for water-saturated and dry targets are indistinguishable.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1029/91GL00214 DOIArticle
http://onlinelibrary.wiley.com/doi/10.1029/91GL00214/abstractPublisherArticle
Additional Information:© 1991 by the American Geophysical Union. Paper number 91GL00214. Received: March 27, 1990 Revised: November 5, 1990. Accepted: November 15, 1990. Research supported under AFOSR-89-0547 and by National Aeronautics and Space Administration. Contribution #4827, Division of Geological and Planetary Sciences. We thank two reviewers for comments.
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Air Force Office of Scientific Research (AFOSR)AFOSR-89-0547
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Issue or Number:2
Record Number:CaltechAUTHORS:20141023-090958603
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20141023-090958603
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:50722
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:23 Oct 2014 19:06
Last Modified:03 Oct 2019 07:26

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