Estimating Thermal Material Properties Using Solar Loading Lock-in Thermography

Applied Sciences

Samuel Klein¹  Hans-Georg Herrmann¹  Henrique Fernandes² 

[1] Chair for Lightweight Systems, Saarland University, Campus E3 1, 66123 Saarbrücken, Germany;Faculty of Computing, Federal University of Uberlandia, Uberlandia 38408-100, Brazil;

关键词: infrared thermography;    solar loading thermography;    lock-in thermography;    passive thermography;    thermal thickness;    thermal effusivity;   

DOI  :  10.3390/app11073097

来源: DOAJ

【 摘 要 】

This work investigates the application of lock-in thermography approach for solar loading thermography applications. In conventional lock-in thermography, a specimen is subjected to a periodically changing heat flux. This heat flux usually enters the specimen in one of three ways: by a point source, a line source or an extended source (area source). Calculations based on area sources are particularly well suited to adapt to solar loading thermography, because most natural heat sources and heat sinks can be approximated to be homogenously extended over a certain region of interest. This is of particular interest because natural heat phenomena cover a large area, which makes this method suitable for measuring large-scale samples. This work investigates how the extended source approximation formulas for determining thermally thick and thermally thin material properties can be used in a naturally excited setup, shows possible error sources, and gives quantitative results for estimating thermal effusivity of a retaining wall structure. It shows that this method can be used on large-scale structures that are subject to natural outside heating phenomena.

【 授权许可】

Unknown