Evaluation of optical space transmission performance for rotary shaft using FBG optical fiber sensing

Abstract

Structural health monitoring is intended as a mechanism to ensure the operation and to evaluate the durability of the structure whose use is expected during a long time. It reduces life-cycle costs with ensuring the safety and the reliability of the structural systems. In addition, the optical fiber sensing systems are used for structural health monitoring because the high accuracy measurement and the transmission line, can be combined by the optical fibers. On the other hand, accurate measurement of horsepower for a rotary shaft in ships is needed for higher fuel efficiency and the energy regulation in international shipping. The FBG (Fiber Bragg Grating) optical fibers sensing are applied to measure several strains at different location which are induced by the torsion for the rotary shaft rotating in 100-400 rpm. The measured data of the strains have to be transmitted to the outside of the rotary shaft to use the FBG optical fiber sensing. The optical space transmission system makes it possible to transmit the data of the strains on the surface of the rotary shaft to outside the measurement system. In this study, we propose to use FBG optical fiber sensor to the shaft horsepower meter of main rotary shaft in ship. The optical transmission efficiency of the FBG measurement system is studied by a static and rotational experiment. Based on the experimental results, we verify the effectiveness of the optical space transmission performance of the system, and of the metrics for its improving performance.