Optical fiber multiparameter sensor for real‐time monitoring of thermoplastic composites during in situ consolidation process

Abstract

Temperature and strain are important parameters in the in situ consolidation process of thermoplastic composites and have been monitored based on optical fiber Bragg gratings. A special polyimide fiber grating (PFBG) is used in this article. PFBG can monitor temperatures up to 400°C and strains up to 40,000 με. The wavelengths of the PFBGs are obtained by wavelength demodulation system and fast digital signal processing with field programmable gate array. Temperature and strain in auto fiber placement process of thermoplastic composites are monitored accurately according to wavelengths. During the whole consolidation process, temperatures have been monitored with the accuracy of 0.1°C in the range of 100–250°C and strains have been monitored with the accuracy of 1 με in the range of −250 to 500 με. The validity and correctness of the results have been validated by the thermocouple and the strain gauge.

Advances in structural analysis and process monitoring of thermoplastic composite pipes

“…Zhan et al [ 129 ] discussed the FBG sensing principle and the major techniques as well as prioritizing the wavelength demodulation. It was deduced that high speed optic fibre grating demodulation technology is mainly applied to optic fibre grating sensing in the thermoplastic composite field.…”