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Fiber optic transverse pressure detection technology for structural health monitoring

An embedded fiber optic sensor based on the photonic crystal fiber is proposed to measure the transverse stress in composited material for structural health monitoring. The sensing principle has been analyzed and validated by experiments. The 0.1%F.S high precision calibration device has been designed to indicated that linear correlation between the wavelength shift of Sagnac loop and pressure, and the good performances of sensor, such as the sensitivity coefficient is 0.1285nm/N, linearity is accessible to 1.02%F.S, maximum error is 3%F.S. Other experiments have been done by a material testing machine on the sensor, which have shown that the sensitivity coefficient is increasing with sensing length but immune with the shape of sensor. The sensor will be suitable for solving the problem of high precision online pressure monitoring in some complex structure health monitoring.