Application of Electronic Speckle Pattern Interferometry to measure thermal strains of thin layered structures
Keywords:speckle interferometry, thermal strain, coefficient of thermal expansion
Applications of the Electronic Speckle Pattern Interferometry (ESPI) for the determination of the coefficient of thermal expansion (CTE) and thermal behaviour of a thin layered foils is investigated in this paper. A heating system was designed for applying thermal load and ESPI technique delivers the full-field thermal deformation fields of the test sample due to the change in temperature. The normal strain is calculated for full-field analysis of thermal expansion of the specimen. For validation, the CTE of an aluminium sample is determined and compared with the textbook value, validating the proposed experimental set-up and the sensitivity and accuracy of the applied experimental technique. The CTE and stress concentration at interface due to thermal loads of a layered thin structure consisting of two different materials is measured. The results reveal that the ESPI is a proper and effective tool for full-field thermal behaviour analysis and CTE measurement.
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