STUDY OF STRUCTURAL FEATURES OF ROCKS BASED ON SPECTRAL CHARACTERISTICS OF BROAD-BAND ULTRASOUND SIGNALS PASSED THROUGH GEOMATERIAL

A brief overview of non-destructive methods of obtaining information about the internal structure and phase composition of samples of geomaterials is given. Special attention is paid to optical-acoustic methods. Theoretical estimates of the spectra of optical-acoustic signal have been made. Necessary for studies of rock samples frequency range was defined. the estimates of necessary parameters of the excited longitudinal waves of ultrasonic pulses to determine the grain size and microcracks were made. The possibility of controlling the pulse parameters by choosing opto-acoustic generator material was shown. Generation of high-frequency part of the spectrum of the excited signal can be provided by the sharp rise of the leading edge exponentially with an exponent equal to the product of the absorption coefficient on the velocity of propagation of longitudinal waves in optical-acoustic transducer material.
The decline of this pulse determines the low-frequency part of the spectrum. The influence on the spectral characteristics of the diffraction and scattering at inhomogeneities geomedium was made. The spectra of the broadband acoustic signals to opto-acoustic generators made of different materials, with different laser pulse durations, as well as the diffraction and scatteringwere obtained. Features of the change of the spectra of scattering in dependence on the characteristic scales of grains (Rayleigh, stochastic and diffuse scattering). It has been shown that fixing the frequency corresponding to transitions from one area to another, it is possible to estimate the characteristic scale of scatterers: the maximum, minimum and average. Thus, by measuring the amplitude spectra of the source signal and transmitted through the sample, it is possible to determine the characteristic size of the grains.

The study has been supported by the Russian Science Foundation, Grant No. 161710181.

Keywords

Internal structure, phase composition of samples; amplitude spectra of optical-acoustic signal; opto-acoustic generator; frequency dependence of scattering coefficient; characteristic scales of grains.

Issue number: 2
Year: 2017
ISBN:
UDK: 552.1
DOI:
Authors: Ertuganova E. A., Vinnikov V. A., Shibaev I. A., Pavlov I. A.

About authors: Ertuganova E.A., Candidate of Technical Sciences, Assistant Professor, Vinnikov V.A., Doctor of Physical and Mathematical Sciences, Head of Chair, e-mail: evgeny.vinnikov@gmail.com, Shibaev I.A., Mining Engineer, Pavlov I.A.1, Student, Mining Institute, National University of Science and Technology «MISiS», 119049, Moscow, Russia.

REFERENCES:
1. Lingtao Mao, Jianping Zuo, Zexun Yuan, Fu-Pen Chiang. Full-field mapping of internal strain distribution in red sand stones specimen under compression using digital volumetric speckle photography and X-ray computed tomography. Journal of Rock Mechanics and Geotechnical Engineering. 2015, v. 7, P. 136–146.
2. Adam J., Schreurs G., Kinkmuller M., Wieneke M. 2D/3D strain localization and fault simulation in analogue experiments: insights from X-ray computed tomography and tomographic image correlation. Bolletino di Geofisica Teorica ed Applicata. 2008, 49 (Supp.2):21–2.
3. Haskin L. A. Raman spectroscopy for mineral identification and quantification for in situ planetary surface analysis: A point count method. Journal of Geophysical Research 102:19293, 2007.
4. Ying G. Automated scanning electron microscope based mineral liberation analysis, Journal of Minerals and Materials Characterization and Engineering 2:33-41, 2003.
5. Bruyndonckx P. et al. Progress in development of a laboratory microXRF-microCT system. Proceedings of SPIE: Developments in X-ray Tomography VII:7804–7845, 2010.
6. Mutina A., Koroteev D., Using D. X-Ray microtomography for the 3D mapping of minerals. Microscopy and Analysis, 26(2), March 2012.
7. Simonova V. A., Savateeva E. V., Karabutov A. A., Karabutov A. A. (ml.), Kaptil’nyy A. G., Ksenofontov D. M., Podymova N. B. Vestnik Rossiyskogo fonda fundamental’nykh issledovaniy, 2012, no 3 (83), pp. 10–20.
8. Karabutov A. A., Podymova N. B., Cherepetskaya E. B., Makarov V. A., Sokolovskaya Yu. G. Laser-Ultrasonic Method for Measuring the Local Elastic Moduli of Porous Isotropic Composite Materials. International Journal of Chemical, Molecular, Nuclear, Materials
and Metallurgical Engineering, v. 9, № 10, P. 1168–1171.
9. Burov V. A., Darialashvili P. I., Evtukhov S. N., Rumyantseva O. D. New informative possibilities of active-passive thermoacoustic tomography. Acoust. Imaging. Ed. W.Arnold and S. Hirsekorn, 2004, v. 27, P. 305–313.
10. Stanke F. E., Kino G. S. A unified theory for elastic wave propagation in polycrystalline materials. J. Acoust. Soc. Am., 1984, V. 75, P. 234–238.
11. Goebbels K., Hirsek S. A new ultrasonic method for stress determination in textured materials. NDT International, Volume 17, Issue 6, December 1984, P. 337–341.
12. Dascha Dobrovolskij, Sigrun Hirsekorn, Martin Spies. Simulation of Ultrasonic Materials Evaluation Experiments Including Scattering Phenomena due to Polycrystalline Microstructure. Physics Procedia 70:644–647. December 2015.
Subscribe for our dispatch