13 June 2001 Shearographic NDT of joined surfaces using multiple-frequency sweep
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Proceedings Volume 4317, Second International Conference on Experimental Mechanics; (2001) https://doi.org/10.1117/12.429594
Event: Second International Conference on Experimental Mechanics, 2000, Singapore, Singapore
Abstract
Shearography, which enables direct measurement of surface slopes under lax environmental stability, is a practical optical tool for measurement and inspection. When applied to flaw detection, conventional shearography requires recording of two sheared-images of the test structure using an image- shearing camera - one before and another after the application of quasi-static load-increment. The resulting phase-change will be perturbed at the region where a flaw is present, when compared with that of a defect-free identical test structure. With time-average shearography, the test object is subjected to vibration excitation, and this is useful for inspection open-boundaries delaminations. A major drawback with the use of single excitation frequency is the need to vibrate the test object within an appropriate frequency range, as otherwise the test data obtained will not readily reveal the defect. This paper describes a new method, based on the use of multiple frequency sweep, which addresses this concern. The Diagnostic Map that is proposed in this paper also enables rapid detection and unambiguous assessment of the soundness of adhesive and mechanically fastened joints. Thus, the user can conduct test with little training received.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Y.Y. Hung, Y.Y. Hung, Huai Min Shang, Huai Min Shang, } "Shearographic NDT of joined surfaces using multiple-frequency sweep", Proc. SPIE 4317, Second International Conference on Experimental Mechanics, (13 June 2001); doi: 10.1117/12.429594; https://doi.org/10.1117/12.429594
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