Mass spring lattice modeling of the scanning laser source technique

Younghoon Sohn*, Sridhar Krishnaswamy

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

68 Scopus citations

Abstract

The scanning laser source (SLS) technique is a promising new laser ultrasonic tool for the detection of small surface-breaking defects. The SLS approach is based on monitoring the changes in laser generated ultrasound as a laser source is scanned over a defect. Changes in amplitude and frequency content have been observed for ultrasound generated by the laser over uniform and defective areas. In this paper, the SLS technique is simulated numerically using the mass spring lattice model. Thermoelastic laser generation of ultrasound in an elastic material is modeled using a shear dipole distribution. The spatial and temporal energy distribution profiles of typical pulsed laser sources are used to model the laser source. The amplitude and spectral variations in the laser generated ultrasound as the SLS scans over a large aluminum block containing a small surface-breaking crack are observed. The experimentally observed SLS amplitude and spectral signatures are shown to be captured very well by the model. In addition, the possibility of utilizing the SLS technique to size surface-breaking cracks that are sub-wavelength in depth is explored.

Original languageEnglish (US)
Pages (from-to)543-551
Number of pages9
JournalUltrasonics
Volume39
Issue number8
DOIs
StatePublished - Jun 1 2002

Keywords

  • Laser ultrasonics
  • Mass spring lattice model
  • Nondestructive testing
  • Scanning laser source technique
  • Surface-breaking cracks

ASJC Scopus subject areas

  • Acoustics and Ultrasonics

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