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Proceedings Paper

Material characterization by laser speckle photometry
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Paper Abstract

The damage and stress conditions of large industrial components have to be tested continuously. Especially welding processes in the field of coal production demand a nondestructive monitoring of internal stresses under an external load. In a first step, a new optical method, Laser Speckle Photometry was used during laboratory welding experiments under tensile and bending loads at high strength construction steels. Laser Speckle Photometry is a fast and contactless method for measuring spatial-temporal dynamics of speckle field with high temporal resolution after local heat excitation. The thermally induced change in the material structure causes changes in the speckle-field, which is formed by a probing laser. The shift of the speckle-field is analyzed by statistical methods, using correlation functions. The result of processing is the two-dimensional distribution of thermal diffusivity coefficient correlated to porosity, materials strain or hardness [1-3]. Here, the results of the welding experiments under load are presented. It is shown, that the Laser Speckle Photometry is a suitable technique for nondestructive monitoring and characterization of internal material stresses under external load.

Paper Details

Date Published: 11 September 2012
PDF: 5 pages
Proc. SPIE 8413, Speckle 2012: V International Conference on Speckle Metrology, 841315 (11 September 2012); doi: 10.1117/12.978246
Show Author Affiliations
Beatrice Bendjus, Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren (Germany)
Ulana Cikalova, Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren (Germany)
Juergen Schreiber, Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren (Germany)


Published in SPIE Proceedings Vol. 8413:
Speckle 2012: V International Conference on Speckle Metrology
Ángel Fernandez Doval; Cristina Trillo, Editor(s)

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