Paper
10 September 2004 Non/destructive testing (NDT) and vibration analysis of defects in components and structures using laser diode shearography
Wolfgang Steinchen, Ymin Gan, Gerhard Kupfer, Peter Mackel
Author Affiliations +
Abstract
One of the most interesting and useful applications of shearographic interferometry is the detection, visualisation and measurement of the mechanical vibration of opaque objects. Until now the time-average shearography is a qualitative interferometric method for determining the oscillating loadings. The detected gradient of the deformation can be determined by changing the shearing distance. The fringes of the moving object are often faded and become clearer by filtering with FFT and against an uniform background intensity. The fringes formed in time-average shearography of sinusoidal motions have an irradiance described by the Bessel function Jo2. Quantitative interpretation of the shearogram requires a more precise analysis. Such a technique for extending or decreasing the sensitivity of vibration measurements and for determining the relative phase of vibration across the object surface is the stroboscopic illumination. Stroboscopic shearographic interferometry is a technique which compensates the deficiencies of time-average shearography at the expense of some increase in experimental complexity. However more complex is the recording of stroboscopic shearograms by using two pulses from a double-pulse laser.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Wolfgang Steinchen, Ymin Gan, Gerhard Kupfer, and Peter Mackel "Non/destructive testing (NDT) and vibration analysis of defects in components and structures using laser diode shearography", Proc. SPIE 5457, Optical Metrology in Production Engineering, (10 September 2004); https://doi.org/10.1117/12.545906
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Shearography

Semiconductor lasers

Fringe analysis

Bessel functions

Vibrometry

Interferometry

Nondestructive evaluation

Back to Top