Measurements of Elastic Modulus Using Laser-Induced Surface Waves

1994 ◽  
Vol 356 ◽  
Author(s):  
D. J. Chang ◽  
S. T. Amimoto ◽  
R. W. Gross ◽  
T. S. Glenn
Keyword(s):  
Elastic Modulus ◽  
Surface Waves ◽  
Acoustic Waves ◽  
Detection Method ◽  
Surface Acoustic Waves ◽  
Pulsed Laser ◽  
Fused Silica ◽  
Knife Edge ◽  
Generate Surface ◽  
Edge Detection Method

AbstractMeasurements of the elastic modulus of fused silica, 6061-T6 and 7075-T651 aluminum alloys, GaAs, Ge, and Si samples are reported. A pulsed laser is used to generate surface acoustic waves in a sample and the wave velocity is measured using a knife-edge detection method. From the velocity of the surface waves the elastic modulus can be calculated.[1] Extension of this work to thin films is discusssed.

scholarly journals Streaming by leaky surface acoustic waves

2010 ◽  
Vol 467 (2130) ◽  
pp. 1779-1800 ◽  
Author(s):  
J. Vanneste ◽  
O. Bühler
Keyword(s):  
Surface Waves ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Acoustic Streaming ◽  
Stokes Drift ◽  
Mean Flow ◽  
Matched Asymptotics ◽  
Flow Generation ◽  
Solid Liquid Interface ◽  
Solid Liquid

Acoustic streaming, the generation of mean flow by dissipating acoustic waves, provides a promising method for flow pumping in microfluidic devices. In recent years, several groups have been experimenting with acoustic streaming induced by leaky surface waves: (Rayleigh) surface waves excited in a piezoelectric solid interact with a small volume of fluid where they generate acoustic waves and, as result of the viscous dissipation of these waves, a mean flow. We discuss the computation of the corresponding Lagrangian mean flow, which controls the trajectories of fluid particles and hence the mixing properties of the flows generated by this method. The problem is formulated using the averaged vorticity equation which extracts the dominant balance between wave dissipation and mean-flow dissipation. Particular attention is paid to the thin boundary layer that forms at the solid/liquid interface, where the flow is best computed using matched asymptotics. This leads to an explicit expression for a slip velocity, which includes the effect of the oscillations of the boundary. The Lagrangian mean flow is naturally separated into three contributions: an interior-driven Eulerian mean flow, a boundary-driven Eulerian mean flow and the Stokes drift. A scale analysis indicates that the latter two contributions can be neglected in devices much larger than the acoustic wavelength but need to be taken into account in smaller devices. A simple two-dimensional model of mean flow generation by surface acoustic waves is discussed as an illustration.

Pulsed laser-stimulated surface acoustic waves in p-CdTe crystals

2001 ◽  
Vol 35 (8) ◽  
pp. 924-926 ◽  
Author(s):  
A. Baidullaeva ◽  
A. I. Vlasenko ◽  
É. I. Kuznetsov ◽  
A. V. Lomovtsev ◽  
P. E. Mozol’ ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Pulsed Laser

Surface Wave Propagation in Thin Silver Films under Residual Stress

2002 ◽  
Vol 57 (1-2) ◽  
pp. 58-64
Author(s):  
A. Njeh ◽  
D. Schneider ◽  
H. Fuess ◽  
M. H. Ben Ghozlen
Keyword(s):  
Residual Stresses ◽  
Phase Velocity ◽  
Surface Waves ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Dispersion Curves ◽  
Silver Films ◽  
Surface Wave Propagation ◽  
Relative Change ◽  
Good Agreement

Investigations using surface acoustic waves provide information on the elastic properties of thin films. Residual stresses change the phase velocity of the surface waves. We have calculated the phase velocity and dispersion of surface waves in thin silver films with a strong [111]-fibre texture. A non-linear description of surface waves propagating along the [110]-direction of the substrate has been developed on the basis of an acoustoelastic theory, taking into account residual stresses. The relative change Δc/c of the velocity v was found to be linear for large excitation frequencies. The dispersion curves were measured using a photoacoustic method. For sputtered polycrystalline thin silver films we found good agreement between the experimental and calculated dispersion curves for frequencies up to 225 MHz

Surface Wave Propagation in Thin Silver Films under Residual Stress

2002 ◽  
Vol 57 (9-10) ◽  
pp. 58-64
Author(s):  
A. Njeh ◽  
T. Wieder ◽  
D. Schneider ◽  
H. Fuess ◽  
M. H. Ben Ghozlen
Keyword(s):  
Residual Stresses ◽  
Phase Velocity ◽  
Surface Waves ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Dispersion Curves ◽  
Silver Films ◽  
Surface Wave Propagation ◽  
Relative Change ◽  
Good Agreement

Investigations using surface acoustic waves provide information on the elastic properties of thin films. Residual stresses change the phase velocity of the surface waves. We have calculated the phase velocity and dispersion of surface waves in thin silver films with a strong [111]-fibre texture. A non-linear description of surface waves propagating along the [110]-direction of the substrate has been developed on the basis of an acoustoelastic theory, taking into account residual stresses. The relative change Δv/v of the velocity v was found to be linear for large excitation frequencies. The dispersion curves were measured using a photoacoustic method. For sputtered polycrystalline thin silver films we found good agreement between the experimental and calculated dispersion curves for frequencies up to 225 MHz.

The converging-surface-acoustic-wave technique: anaylsis and applications to nondestructive evaluation

1986 ◽  
Vol 64 (9) ◽  
pp. 1324-1329 ◽  
Author(s):  
P. Cielo ◽  
C. K. Jen ◽  
X. Maldague
Keyword(s):  
Acoustic Waves ◽  
Laser Interferometer ◽  
Surface Acoustic Waves ◽  
Pulsed Laser ◽  
Ultrasonic Pulse ◽  
Planar Defects ◽  
Wave Technique ◽  
Pulse Arrival ◽  
Pulsed Laser Beam

Converging surface-acoustic waves (SAW) are generated by irradiating the inspected material with an annular-shaped pulsed laser beam. The converging-SAW pulse arrival is detected by a laser interferometer focused on the center of the annulus, where the converging effect produces a strong amplification of the ultrasonic pulse. This technique can be applied either to the detection of defects or to the characterization of the material by measuring the SAW velocity or attenuation. In this paper we present an analysis of the converging-wave propagation in order to explain some features of the detected signal, such as its shape and amplitude for different positions of the probing beam. A comparison with the signal intensities expected for a diverging as well as a collimated SAW is also presented. Applications of this technique to the characterization of anisotropic materials as well as to the detection of subsurface planar defects are presented and discussed.

An integrated method for material properties characterization based on pulsed laser generated surface acoustic waves

2013 ◽  
Vol 112 ◽  
pp. 249-254 ◽  
Author(s):  
Yannis Orphanos ◽  
Vasilis Dimitriou ◽  
Evaggelos Kaselouris ◽  
Efthimios Bakarezos ◽  
Nikolaos Vainos ◽  
...  
Keyword(s):  
Material Properties ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Pulsed Laser ◽  
Integrated Method ◽  
Properties Characterization

Low-frequency surface acoustic waves in a collisional plasma

1993 ◽  
Vol 50 (1) ◽  
pp. 71-77 ◽  
Author(s):  
S. V. Vladimirov ◽  
M. Y. Yu
Keyword(s):  
Surface Waves ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Low Frequency ◽  
Collisional Plasma ◽  
Ion Acoustic ◽  
Acoustic Surface Waves

Ion-acoustic surface waves in a highly collisional plasma are considered. It is shown that the dispersion and damping of these waves differ considerably from those for a weakly collisional plasma.

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