Numerical and experimental investigation of FBG strain response at cryogenic temperatures

26th International Cryogenic Engineering Conference & International Cryogenic Materials Conference 2016

材料科学;物理学

Venkatesan, V.N.^1 ; Ramalingam, R.^1

Institute of Technical Physics (ITEP), Karlsruhe Institute of Technology (KIT), Germany^1

关键词: Bragg wavelength;    Bragg wavelength shift;    Cryogenic temperatures;    Experimental investigations;    Fiber Bragg Grating Sensors;    Linear polynomials;    Strain sensitivity;    Tensile machines;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/171/1/012133/pdf
DOI  :  10.1088/1757-899X/171/1/012133

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Strain response of FBG sensors are investigated at various temperatures from 298 K to 4.2 K. Numerical modelling is carried out for acrylate coated, substrate-free fiber Bragg grating (FBG) sensors at room temperature of 298 K and cryogenic temperatures of 77 K, 10 K and 4.2 K. A 1550 nm Bragg wavelength (λB) FBG sensor is modelled and simulated for applied strain () ranging from 0 to 800 μm/m. The Bragg wavelength shifts (ΔλB) thus obtained are compared with the experimentally investigated values obtained by subjecting the FBG sensor to axial strain, with its sensing part not being bonded to any surface. The MTS25 tensile machine with a cryostat under vacuum conditions (10-4mbar pressure) is used for the experiments and the required temperatures are maintained using liquid Nitrogen (LN2) and compressed Helium gas (He). The Bragg wavelength shift (ΔλB) versus induced strain () is regressed with a linear polynomial function and the strain sensitivity obtained in both the cases are discussed.