Three-dimensional SAFT imaging for anisotropic materials using photoacoustic microscopy

K. Nakahata, K. Karakawa, K. Ogi, K. Mizukami, K. Ohira, M. Maruyama, S. Wada, T. Namita, T. Shiina

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

A pulsed laser illuminates a target zone that causes rapid thermoelastic expansion, generating broadband high-frequency ultrasonic wave (photoacoustic wave, PA wave). We developed a PA microscopy (PAM) with a confocal area of laser and ultrasonic wave for applications in nondestructive testing (NDT). The synthetic aperture focusing technique (SAFT) is applied in the PAM for the three-dimensional (3D) imaging of interior flaws. Here, we report proof-of-concept experiments for the NDT of a subsurface flaw in a thin laminar material. Graphical abstract (a) shows a specimen of carbon-fiber-reinforced plastic (CFRP) with an artificial delamination. Here, it should be noted that the group velocity varies directionally due to the strong anisotropy of the CFRP specimen (see Graphical abstract (b)). By considering the group velocity distribution in the SAFT, the shape and location of the subsurface delamination were accurately estimated as shown in Graphical abstract (c). Coating the surface of the CFRP specimen with a light-absorbent material improved the amplitude of the PA wave. This finding showed that the signal-to-noise ratio of the waves scattered from the flaws can be improved.

Original languageEnglish
Pages (from-to)82-87
Number of pages6
JournalUltrasonics
Volume98
DOIs
Publication statusPublished - 2019 Sep
Externally publishedYes

Keywords

  • Anisotropy
  • Carbon fiber reinforced plastic (CFRP)
  • Photoacoustic microscopy (PAM)
  • Subsurface flaw
  • Synthetic aperture focusing technique (SAFT)

ASJC Scopus subject areas

  • Acoustics and Ultrasonics

Fingerprint

Dive into the research topics of 'Three-dimensional SAFT imaging for anisotropic materials using photoacoustic microscopy'. Together they form a unique fingerprint.

Cite this