11 September 2012 Material characterization by laser speckle photometry
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Proceedings Volume 8413, Speckle 2012: V International Conference on Speckle Metrology; 841315 (2012) https://doi.org/10.1117/12.978246
Event: SPECKLE 2012: V International Conference on Speckle Metrology, 2012, Vigo, Spain
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.
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Beatrice Bendjus, Ulana Cikalova, Juergen Schreiber, "Material characterization by laser speckle photometry", Proc. SPIE 8413, Speckle 2012: V International Conference on Speckle Metrology, 841315 (11 September 2012); doi: 10.1117/12.978246; https://doi.org/10.1117/12.978246

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