Measurement of surface torsional strain distributions on rotary shaft using FBG optical fiber sensing

Abstract

Structural health monitoring has been used to confirm the durability evaluation and safety of a structure in which long-term use is required. Because the transmission loss of the optical fiber sensor is extremely small, it can measure the present status of structures from far away. Generally the FBG (Fiber Bragg Grating) optical sensing systems are often used to get reliable indices from structures. The shipping industry recently, there has been a growing interest in fuel efficiency improvements and energy regulation in international shipping. Therefore, during sailing, to measure the exact power of the main shaft of the ship has become important. We proposed the monitoring system using space optical transmitting of the FBG optical fiber to get information from a rotational shaft. And we evaluated the performance of the space optical transmission of the FBG optical fiber sensing system for rotational shaft in the previous study. Consequently, we reported that it can be effectively measured and space optical transmission metric is effective for performance prediction. In this paper, the strain and the temperature on the rotating torsion shaft, is measured by the FBG optical fiber sensor and the space optical transmission. We confirm reliability of the information that is retrieved from the rotating shaft subjected to torsion in the experiment. The conditions for reliable data from the rotating shaft under loading is obtained on the basis of the experimental results of the proposed systems.

Keywords

• fbg sensor
• strain distribution
• structural health monitoring
• optical measurement
• rotating body
• optical space transmission