Nonlinear Wave Propagation Study
Semi-annual technical rept. no. 3, 1 Dec 1984-31 May 1985
ROCKWELL INTERNATIONAL CORP THOUSAND OAKS CA SCIENCE CENTER
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In this document we report the results of combined high amplitude tensile and compressive loading experiments on four different rock types Westerly granite, Boise sandstone, Berea sandstone, and Indiana limestone. The details of the stress-strain hysteresis loops are examined, with emphasis on investigating the elastic and inelastic properties of rocks at nonlinear amplitudes in both tension and compression. The results indicate that the mechanical behavior of rocks can be significantly different in compression than in tension and that the onset of nonlinear effects with increasing strain may not be the same for compressive loads as for tensile loads. All available evidence indicates that the primary relaxation mechanism at nonlinear amplitudes between 10 to the -6th power strain and 0.0001 strain involves intergranular friction. More experimental work in this area will shed light on the issue of linearity vs. nonlinearity at intermediate strains, and also will provide realistic detailed information about rock rheology for the numerical modeling of near-field seismic pulse propagation.
- Geology, Geochemistry and Mineralogy
- Numerical Mathematics