Accession Number : AD0874521

Title :   Attenuation of Stress Waves in Cedar City Quartz Diorite.

Descriptive Note : Technical rept. Sep 68-Mar 70,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF EARTH ATMOSPHERIC AND PLANETARY SCIENCES

Personal Author(s) : Walsh, Joseph B. ; Brace, William F. ; Wawersik, Wolfgang R.

Report Date : JUL 1970

Pagination or Media Count : 86

Abstract : The attenuation of a finite amplitude stress wave in a quartz diorite from Cedar City, Utah, was estimated from static compression tests under confining pressure. Measurements were made at pressures up to 7,500 psi and deviatoric stresses up to 10,000 psi. Energy dissipated was calculated from stress-strain curves for complete loading-unloading cycles. Total relative attenuation, defined as the ratio of the energy lost to the maximum energy stored in the sample, was found to be approximately independent of the level of deviatoric stress. Relative attenuation was about 0.5 at 7,200 psi. Attenuation in Cedar City quartz diorite is about five times greater than the value for a more typical compact granite, apparently because of the loose structure resulting from past alteration. A significant proportion of the energy dissipated arises from work done compacting the rock under pressure, again a characteristic arising from the losse structure of the quartz diorite and unlike typical unaltered igneous rocks. (Author)

Descriptors :   *ROCK FORMING MINERALS, *ANTIMISSILE DEFENSE SYSTEMS, STRESSES, SITE SELECTION, IGNEOUS ROCK, MICROSTRUCTURE, GRAIN SIZE, POROSITY, STRAIN(MECHANICS), HYSTERESIS, CRACKS, TEST METHODS, QUANTITATIVE ANALYSIS.

Subject Categories : Geology, Geochemistry and Mineralogy
      Antimissile Defense Systems

Distribution Statement : APPROVED FOR PUBLIC RELEASE