Abstract
We apply the technique of ultrasonic pulse spectroscopy to measure the interference effects between two shear waves propagating in specimens loaded in uniaxial compression. We show that the power spectrum of an echo containing both fast and slow components of a shear wave will exhibit periodic minima. The periodicity exhibited in the spectrum is 1/Δτ, where Δτ is the difference in arrival time between the fast and slow waves. A change in the state of stress which produces a change in the two shear velocities results in a stress-dependent change in wave-arrival times. Because of this velocity change, the frequency at which a particular minimum occurs in the spectrum changes, and this can be used to indicate the state of stress in the material.
Our results indicate that, if the spectrum minima frequencies could be resolved to within 10 kHz, the principal-stress differences within 36 psi (0.251 MPa) could be measured in specimens of aluminum 1 in. (2.54 cm) thick. Inherent in analyzing and measuring echo-interference effects is a single-echo requirement. Thus, transducer coupling effects are minimized and measurements in highly attenuating materials or at high frequencies in normal attenuating materials are possible. This technique shows considerable promise as a means of measuring and monitoring the applied stresses in materials.
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References
Bergman, R. H. andShahbender, R. A., “Effect of Statically Applied Stresses on the Velocity of Propagation of Ultrasonic Waves,”J. Appl. Phys.,29,1736–1738 (1958).
Benson, R. W. andRaelson, V. J., “Acoustoelasticity,”Prod. Engrg.,30,56–59 (1959).
Elion, H. A., “Recent Advances in New Areas of Nondestructive Testing,”Nondestr. Test.,18,180–182 (1960).
Hsu, N. N., “Acoustic Birefringence and the Use of Ultrasonic Waves for Experimental Stress Analysis,”Experimental Mechanics,14 (5),169–176 (May 1974).
Noronha, P. J. andWert, J. J., “An Ultrasonic Technique for the Measurement of Residual Stress,”J. of Test and Eval.,3,147–152 (1975).
Durelli, A. J. andRiley, W. F., “Introduction to Photomechanics, Ch. 3, Prentice-Hall, Inc., N. J. (1965).
Hughes, D. S. andKelly, J. L., “Second-Order Elastic Deformation of Solids,”Phys. Rev.,92,1145–1149 (1953).
Papadakis, E. P., “Ultrasonic Spectroscopy Applied to Double Refraction in Worked Metals,”J. Acoust. Soc. Am.,55,783–784 (1974).
Papadakis, E. P., “Ultrasonic Phase Velocity by the Pulse-Echo-Overlap Method Incorporating Diffraction Phase Corrections,”J. Acoust. Soc. Am.,42,1045–1051 (1967).
Sachse, W., “Measurement of the Elastic Moduli of Continuous-Filament and Eutectic Composite Materials,”J. Comp. Matls.,8,378–390 (1974).
Hsu, N. N. andSachse, W., “Generation and Detection of Plane-Polarized Ultrasound with a Rotatable Transducer,”Rev. Sci. Instr.,46,923–926 (1975).
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Blinka, J., Sachse, W. Application of ultrasonic-pulse-spectroscopy measurements to experimental stress analysis. Experimental Mechanics 16, 448–453 (1976). https://doi.org/10.1007/BF02324101
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DOI: https://doi.org/10.1007/BF02324101