Special Issue "Opto-Acoustic Characterization of Metals"

A special issue of Metals (ISSN 2075-4701).

Deadline for manuscript submissions: closed (30 September 2019).

Special Issue Editor

Prof. Sanichiro Yoshida
E-Mail Website
Guest Editor
Department of Chemistry and Physics, Southeastern Louisiana University, SLU 10878, Hammond, LA 70402, USA
Interests: characterization of materials' mechanical properties, optical methods, optoacoustic methods, field theories, interferometry, dynamic analysis

Special Issue Information

Dear Colleagues,

This Special Issue focuses on optoacoustic techniques to characterize various properties of metals including metallic compounds and metal matrix composites. Optical and acoustic waves compensate each other. Light is a transverse wave and, in most cases, does not propagate through metals. Sound is a longitudinal wave and generally travels through metals. The oscillation frequency of light is orders of magnitude higher than sound. Slow dynamics can be pseudo-static at the optical frequency and can resonate at the acoustic frequency. Fast dynamics can resonate at the optical frequency but too fast for the acoustic frequency to respond. The acoustic wave dynamics are essentially the elastic response of the material. The optical wave dynamics are associated with the electromagnetic properties of the material. It is relatively easy to find a coherent optical source but not a coherent acoustic source. By combining these contrastive properties of the two waves, we can make an analysis that we would not be able to make with the use of either wave only. As an example, using a laser to record the displacement and an acoustic signal to probe the elastic constant of a metal specimen under deformation, we can directly analyze the constitutive characteristics. The use of an optical source to trigger an acoustic event such as laser acoustic nondestructive testing makes the system remotely operational. The use of an acoustic source to excite vibrations and read out the response with a laser, such as full-field imaging of acoustic resonant motion, increases the resolution of the analysis.

Original research papers and review papers related to the above techniques and findings resulting from the application of these techniques are welcome. Application of optical and acoustic methods to the same study is preferred, but application of an optical or acoustic method is also considered for publication.

Prof. Sanichiro Yodhida
Guest Editor

Keywords

  • Optical metrology
  • Acoustic emission
  • Optoacoustic nondestructive testing
  • Acoustic resonance
  • Electronic speckle-pattern interferometry
  • Acoustic imaging
  • Acoustic microscopy

Published Papers (3 papers)

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Research

Open AccessArticle
Ultrasonic Bonding of Multi-Layered Foil Using a Cylindrical Surface Tool
Metals 2019, 9(5), 505; https://doi.org/10.3390/met9050505 - 29 Apr 2019
Cited by 1
Abstract
A cylindrical tool was applied for ultrasonic bonding of multi-layered copper foil and a copper sheet to prevent damage to the foil during bonding. The strength of the joints bonded with the cylindrical tool was comparable to that of the joints bonded with [...] Read more.
A cylindrical tool was applied for ultrasonic bonding of multi-layered copper foil and a copper sheet to prevent damage to the foil during bonding. The strength of the joints bonded with the cylindrical tool was comparable to that of the joints bonded with a conventional knurled tool. The effect of the cylindrical surface tool on bondability was investigated thorough relative motion behaviors between the tool surface and the bonding materials, as well as on bond microstructure evolution. The relative motion was visualized with in-situ observation using a high-speed camera and digital image correlation. At shorter bonding times, relative motions occurred at the bonding interfaces of the foil and the copper sheet. Thereafter, the relative motion between the tool and the bonding material became predominant owing to bond formation at the bonding interface, resulting in a macroscopic plastic flow in the bonded region. This relative motion damaged the foil in knurled tool bonding, and the cylindrical tool achieved bonding without any damage. Full article
(This article belongs to the Special Issue Opto-Acoustic Characterization of Metals)
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Open AccessArticle
Sparse-TFM Imaging of Lamb Waves for the Near-Distance Defects in Plate-Like Structures
Metals 2019, 9(5), 503; https://doi.org/10.3390/met9050503 - 29 Apr 2019
Cited by 2
Abstract
The ultrasonic phased array total focusing method (TFM) has the advantages of high imaging resolution and high sensitivity to small defects. However, it has a long imaging time and cannot realize near-distance defect imaging, which limits its application for industrial detection. A sparse-TFM [...] Read more.
The ultrasonic phased array total focusing method (TFM) has the advantages of high imaging resolution and high sensitivity to small defects. However, it has a long imaging time and cannot realize near-distance defect imaging, which limits its application for industrial detection. A sparse-TFM algorithm is adopted in this work to solve the problem regarding rapid imaging of near- distance defects in thin plates. Green’s function is reconstructed through the cross-correlation of the diffuse full matrix captured by the ultrasonic phased array. The reconstructed full matrix recovers near-distance scattering information submerged by noise. A sparse array is applied to TFM for rapid imaging. In order to improve the imaging resolution, the location of active array elements in the sparse array can be optimized using the genetic algorithm (GA). Experiments are conducted on three aluminium plates with near-distance defects. The experimental results confirm that the sparse-TFM algorithm of Lamb waves can be used for near-distance defects imaging, which increases the computational efficiency by keeping the imaging accuracy. This paper provides a theoretical guidance for Lamb wave non-destructive testing of the near-distance defects in plate-like structures. Full article
(This article belongs to the Special Issue Opto-Acoustic Characterization of Metals)
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Open AccessArticle
Characterization of Microstructural Evolution by Ultrasonic Nonlinear Parameters Adjusted by Attenuation Factor
Metals 2019, 9(3), 271; https://doi.org/10.3390/met9030271 - 26 Feb 2019
Cited by 5
Abstract
The use of an acoustic nonlinear response has been accepted as a promising alternative for the assessment of micro-structural damage in metallic solids. However, the full mechanism of the acoustic nonlinear response caused by the material micro-damages is quite complex and not yet [...] Read more.
The use of an acoustic nonlinear response has been accepted as a promising alternative for the assessment of micro-structural damage in metallic solids. However, the full mechanism of the acoustic nonlinear response caused by the material micro-damages is quite complex and not yet well understood. In this paper, the effect of material microstructural evolution on acoustic nonlinear response of ultrasonic waves is investigated in rolled copper and brass. Microstructural evolution in the specimens is artificially controlled by cold rolling and annealing treatments. The correlations of acoustic nonlinear responses of ultrasonic waves in the specimens corresponding to the microstructural changes are obtained experimentally. To eliminate the influence of attenuation, which was induced by microstructural changes in specimens, experimentally-measured nonlinear parameters are corrected by an attenuation correction term. An obvious decrease of nonlinearity with the increase of grain size is found in the study. In addition, the influences of material micro-damages introduced by cold rolling on the acoustic nonlinear response in specimens are compared with the ones of grain boundaries controlled by heat treatment in specimens. The experimental results show that the degradation of material mechanical properties is not always accompanied by the increase of acoustic nonlinearity generated. It suggested that the nonlinear ultrasonic technique can be used to effectively characterize the material degradations, under the condition that the variations of grain sizes in the specimens under different damage states are negligible. Full article
(This article belongs to the Special Issue Opto-Acoustic Characterization of Metals)
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