Application of wideband laser-ultrasonic spectroscopy for non-destructive control of porosity in carbon plastics with various volume content of carbon fiber

2021 ◽  
Vol 3 ◽  
pp. 76-84
Author(s):  
Yu. G. Sokolovskaya ◽  
◽  
N. B. Podymova ◽  
A. A. Karabutov ◽  
◽  
...  
Keyword(s):  
Phase Velocity ◽  
Acoustic Waves ◽  
Velocity Dispersion ◽  
Relative Dispersion ◽  
Ultrasonic Spectroscopy ◽  
Longitudinal Acoustic ◽  
Phase Velocity Dispersion ◽  
Longitudinal Acoustic Waves ◽  
Non Destructive ◽  
Frequency Dependences

In this work, to obtain the frequency dependences of the phase velocity of longitudinal acoustic waves in composite materials, we use the method of broadband laser-ultrasonic spectroscopy, based on laser thermo-optical excitation of broadband acoustic pulses. Unidirectional carbon fiber reinforced plasticsampes with different volume contents of the matrix and fiber were taken as objects of study.For the studied samples, the frequency dependences of the phase velocity were obtained in the spectral range of 0.8 – 10 MHz, and the existence of the phase velocity dispersion in this range was shown. The phase velocity dispersion of longitudinal acoustic waves in the sample was calculated using the phase spectra of the probe ultrasonic pulse and the pulse transmitted through the sample under study. It is also shown that the relative dispersion of the phase velocity characterizes the porosity of the sample, and the higher the porosity, the greater the relative dispersion. Empirical relations obtained for the relationship between porosity and relative dispersion can be used for the operational non-destructive assessment of the porosity of composites. The results obtained can be useful both for quality control of the materials obtained with the aim of modernizing manufacturing technologies and for predicting the behavior of structures and parts of this material under external loads.

scholarly journals Theoretical and experimental revision of surface acoustic waves on the (100) plane of silicon

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexander Tarasenko ◽  
Radim Čtvrtlík ◽  
Radim Kudělka
Keyword(s):  
Experimental Data ◽  
Phase Velocity ◽  
Acoustic Waves ◽  
Basal Plane ◽  
Velocity Dispersion ◽  
Surface Acoustic Waves ◽  
Azimuthal Angle ◽  
Acoustic Method ◽  
Phase Velocities ◽  
Phase Velocity Dispersion

AbstractThe phase velocity dispersion of the surface acoustic waves on a basal plane of Si(100) has been calculated in the whole range of the azimuthal angle of propagation. We present a detailed description of the calculations. These calculations are compared with the experimental data obtained by a laser acoustic method. Our data convincingly demonstrate the existence of a gap in the spectrum of the phase velocities. The gap means that in a definite range of the phase velocities the SAWs are absent in the whole interval of the azimuthal angles. There is an excellent coincidence between the numerical and experimental data.

Study of Porosity of Carbon Reinforced Plastic Composites Using Broadband Ultrasound Structuroscopy Techniques

2017 ◽  
Vol 755 ◽  
pp. 44-51
Author(s):  
Anton S. Bychkov ◽  
Alexander A. Karabutov ◽  
Elena V. Savateeva ◽  
Yulia G. Sokolovskaya ◽  
Vasily P. Zarubin ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Metal Matrix ◽  
Elastic Moduli ◽  
Epoxy Composites ◽  
Ultrasonic Spectroscopy ◽  
Isotropic Composite ◽  
Plastic Composites ◽  
Reinforced Plastic ◽  
Local Porosity ◽  
Longitudinal Acoustic Waves

Theoretical assessments are given for the use of the through-transition technique of broadband ultrasonic spectroscopy to determine porosity of heterogeneous materials. Experimental measurements of local porosity of composites using the through-transition technique are presented. Dependences of elastic moduli on the concentration of hardening particles and porosity of metal matrix isotropic composite found. Experimental relationship between the phase velocity of longitudinal acoustic waves and the power of structural noise in samples of graphite epoxy composites is obtained.

Finite-Difference Modeling and Characteristics Analysis of Love Waves in Anisotropic-Viscoelastic Media

2021 ◽  
Author(s):  
Shichuan Yuan ◽  
Zhenguo Zhang ◽  
Hengxin Ren ◽  
Wei Zhang ◽  
Xianhai Song ◽  
...  
Keyword(s):  
Finite Difference ◽  
Phase Velocity ◽  
Velocity Dispersion ◽  
Love Waves ◽  
Velocity Anisotropy ◽  
Viscoelastic Media ◽  
Phase Velocities ◽  
Phase Velocity Dispersion ◽  
Anisotropic Elastic ◽  
Attenuation Anisotropy

ABSTRACT In this study, the characteristics of Love waves in viscoelastic vertical transversely isotropic layered media are investigated by finite-difference numerical modeling. The accuracy of the modeling scheme is tested against the theoretical seismograms of isotropic-elastic and isotropic-viscoelastic media. The correctness of the modeling results is verified by the theoretical phase-velocity dispersion curves of Love waves in isotropic or anisotropic elastic or viscoelastic media. In two-layer half-space models, the effects of velocity anisotropy, viscoelasticity, and attenuation anisotropy of media on Love waves are studied in detail by comparing the modeling results obtained for anisotropic-elastic, isotropic-viscoelastic, and anisotropic-viscoelastic media with those obtained for isotropic-elastic media. Then, Love waves in three typical four-layer half-space models are simulated to further analyze the characteristics of Love waves in anisotropic-viscoelastic layered media. The results show that Love waves propagating in anisotropic-viscoelastic media are affected by both the anisotropy and viscoelasticity of media. The velocity anisotropy of media causes substantial changes in the values and distribution range of phase velocities of Love waves. The viscoelasticity of media leads to the amplitude attenuation and phase velocity dispersion of Love waves, and these effects increase with decreasing quality factors. The attenuation anisotropy of media indicates that the viscoelasticity degree of media is direction dependent. Comparisons of phase velocity ratios suggest that the change degree of Love-wave phase velocities due to viscoelasticity is much less than that caused by velocity anisotropy.

scholarly journals The Lamb waves phase velocity dispersion evaluation using an hybrid measurement technique

2018 ◽  
Vol 184 ◽  
pp. 1156-1164 ◽  
Author(s):  
L. Draudviliene ◽  
H. Ait Aider ◽  
O. Tumsys ◽  
L. Mazeika
Keyword(s):  
Phase Velocity ◽  
Measurement Technique ◽  
Velocity Dispersion ◽  
Lamb Waves ◽  
Phase Velocity Dispersion

Interference of opposing longitudinal acoustic waves in an isotropic absorbing plate and a periodic structure with defects

2001 ◽  
Vol 47 (6) ◽  
pp. 721-726 ◽  
Author(s):  
A. A. Karabutov ◽  
V. V. Kozhushko ◽  
I. M. Pelivanov ◽  
G. S. Mityurich
Keyword(s):  
Periodic Structure ◽  
Acoustic Waves ◽  
Longitudinal Acoustic ◽  
Longitudinal Acoustic Waves
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