Accession Number : ADA301757

Title :   Optical Stress Gauge Development for Very High Stresses Piezoraman Measurements and Analysis.

Descriptive Note : Technical rept. 12 Jun 90-31 Jul 94,

Corporate Author : WASHINGTON STATE UNIV PULLMAN DEPT OF PHYSICS

Personal Author(s) : Gupta, Yogendra M.

PDF Url : ADA301757

Report Date : 01 NOV 1995

Pagination or Media Count : 235

Abstract : Experiments and analyses were carried out to demonstrate the use of diamond crystals as very high stress, optical transducers under shock loading. Experimental methods were developed to routinely permit time-resolved measurements (10 ns resolution) of stress induced frequency shifts of the Raman line in shocked diamonds. Plate impact experiments were conducted to achieve peak stresses to 500 kbar for uniaxial strain compression along the 110 and 100 orientations. Over the stress range examined, the Raman shifts in the shocked diamonds were completely reversible. The triple degeneracy of the diamond Raman line was completely lifted for the 1101 ORIENTATION AND PARTIALLY LIFTED FOR THE 1100 orientation. A nonlinear elastic equation of state was developed for diamond. A theoretical model is described for relating the Raman shifts to an arbitrary deformation of the diamond crystals. All of the tensor coefficients in the model can be obtained from the 110 data. The 100 data provide an independent check of the predictive capability of the theoretical model. Good agreement was also observed with available hydrostatic data and uniaxial stress data at low stresses. The present work provides a firm basis for the development of an optical transducer for use at very high stresses. (MM)

Descriptors :   *THERMAL PROPERTIES, *OPTICAL PROPERTIES, *CRYSTAL STRUCTURE, *DIAMONDS, *OPTICAL DETECTORS, *RAMAN SPECTRA, FIBER OPTICS, STRESS ANALYSIS, CRYSTAL LATTICES, LOADS(FORCES), DEFORMATION, SHOCK WAVES, HARMONICS, ELASTIC PROPERTIES, SHOCK(MECHANICS), SINGLE CRYSTALS, STRAIN(MECHANICS), CRYSTALS, BACKSCATTERING, LASER BEAMS, STRENGTH(MECHANICS), THERMAL CONDUCTIVITY, HYDROSTATICS, TRANSDUCERS, CALIBRATION, ABSORPTION SPECTRA, GAGES, INFRARED SPECTRA, AXIAL LOADS, FREQUENCY SHIFT.

Subject Categories : Crystallography
      Atomic and Molecular Physics and Spectroscopy
      Optics
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE