Measurement of the high-temperature strain of UHTC materials using chemical composition gratings

• Published in: Measurement science & technology 2016-05, Vol.27 (5), p.55101
• Main Authors: Xie, Weihua, Meng, Songhe, Jin, Hua, Du, Chong, Wang, Libin, Peng, Tao, Scarpa, F, Huo, Shiyu
• Format: Article
• Language: English
• Subjects: chemical composition gratings; fibre optics sensors; high-temperature application; strain and temperature; ultra-high temperature ceramics
• ISSN: 0957-0233; 1361-6501
• DOI: 10.1088/0957-0233/27/5/055101

This paper proposes a simple bonding and measuring technique to realise silica-based chemical composition gratings' (CCGs) high temperature applications on hot structures. We describe a series of experiments on CCGs to measure the thermal and mechanical response characteristics of ultra-high temperature ceramic (UHTC) materials when the maximum temperature is above 1000 °C. Response characteristics are obtained at the heating and cooling stages. Results show that the wavelength response of the CCGs bonded on the UHTC plate increases non-linearly with increasing temperatures, but decreases almost linearly with decreasing temperatures. The temperature-dependent strain transfer coefficients are calculated theoretically and experimentally; results show that the values of strain transfer coefficients below 1000 °C are significantly affected by the thermal expansion coefficient of the substrate material and the interface. The strain transfer coefficient value tends to vary slowly between 0.616 and 0.626 above 700 °C.