Journal of the Korean Society for Nondestructive Testing (비파괴검사학회지)

The Korean Society for Nondestructive Testing (한국비파괴검사학회)
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Frequency Characteristics of Surface Wave Generated by Single-Line Pulsed Laser Beam with Two Kinds of Spatial Energy Profile Models: Gaussian and Square-Like

  • Seo, Ho-Geon (School of Mechanical Engineering, Hanyang University) ;
  • Kim, Myung-Hwan (School of Mechanical Engineering, Hanyang University) ;
  • Choi, Sung-Ho (Department of Automotive Engineering, Graduate School of Hanyang University) ;
  • Kim, Chung-Seok (Department of Automotive Engineering, Hanyang University) ;
  • Jhang, Kyung-Young (School of Mechanical Engineering, Hanyang University)
  • Received : 2012.06.19
  • Accepted : 2012.08.10
  • Published : 2012.08.30
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Abstract

Using a single-line pulsed laser beam is well known as a useful noncontact method to generate a directional surface acoustic wave. In this method, different laser beam energy profiles produce different waveforms and frequency characteristics. In this paper, we considered two typical kinds of laser beam energy profiles, Gaussian and square-like, to find out a difference in the frequency characteristics. To achieve this, mathematical models were proposed first for Gaussian laser beam profile and square-like respectively, both of which depended on the laser beam width. To verify the theoretical models, experimental setups with a cylindrical lens and a line-slit mask were respectively designed to produce a line laser beam with Gaussian spatial energy profile and square-like. The frequency responses of the theoretical models showed good agreement with experimental results in terms of the existence of harmonic frequency components and the shift of the first peak frequencies to low.

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References

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