Low frequency acoustic microscopy and pattern recognition for studying damaged and anisotropic composites and material defects

M. A. Awal, A. Mahalanobis, Tribikram Kundu

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

In recent years, acoustic microscopy has been found to be very useful for characterizing engineering as well as biologic materials. With the present state of knowledge on acoustic microscopy, one can obtain the surface wave velocity of a homogeneous specimen or coating thickness of a coated material and produce images of near surface internal defects and inhomogeneities in a specimen. Applications of acoustic microscopy for obtaining material properties of anisotropic specimens and detecting material defects at a greater depth are meager because commercially available acoustic microscopes are insensitive to direction-dependent material properties and they, in general, have poor penetration properties because of high operating frequencies. Recently at the University of Arizona an unconventional low frequency (0.5-2.5 MHz) acoustic microscope has been fabricated where the microscope lens has been replaced by two ultrasonic transducers with cylindrical concave faces; one works as a transmitter and the other one works as a receiver. Using this arrangement, it has been found that it is possible to detect internal damages in a material and identify material anisotropy in fiber-reinforced composite plates. These capabilities of the microscope are demonstrated in this paper by presenting some experimental results along with theoretical justifications. Then pattern recognition techniques are used to solve the inverse problem, that is, to predict the type of material defect from reflected acoustic signals.

Original languageEnglish (US)
Pages (from-to)19-28
Number of pages10
JournalJournal of Nondestructive Evaluation
Volume11
Issue number1
DOIs
StatePublished - Mar 1992

Fingerprint

Pattern recognition
Defects
Acoustic microscopes
Composite materials
Materials properties
Microscopes
Coated materials
Ultrasonic transducers
Inverse problems
Surface waves
Transmitters
Lenses
Anisotropy
Acoustics
Acoustic Microscopy
Coatings
Fibers

Keywords

  • Acoustic microscopy
  • composite solid
  • damage
  • defect
  • linear filters
  • pattern recognition
  • ultrasonic signal

ASJC Scopus subject areas

  • Materials Science (miscellaneous)

Cite this

Low frequency acoustic microscopy and pattern recognition for studying damaged and anisotropic composites and material defects. / Awal, M. A.; Mahalanobis, A.; Kundu, Tribikram.

In: Journal of Nondestructive Evaluation, Vol. 11, No. 1, 03.1992, p. 19-28.

Research output: Contribution to journalArticle

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