Development of a new fiber-optic vibration sensor and its application to structural health monitoring of composite structures

摘要

A new fiber-optic vibration sensor has been developed. The sensor is based on new finding that frequency of light wave transmitted through a bended optical fiber is shifted by vibration at the bended region. The principle can be explained that Doppler s effect of the light wave which changes its direction in the optical fiber. Several configurations of the sensor have been designed, and very high sensitivity has been achieved in the extremely wide frequency band by applying laser Doppler velocimeter. Practically numberless sensing points can be arranged on a single optical fiber, and regional monitoring which covers large area of the structures can be achieved. The experimental results show that the sensitivity is almost equivalent to PZT sensor and that failure of composite materials and the adhesive joint can be detected successfully. The durable, low-cost and high-sensitive sensor can show a new scope to structural health monitoring in the very variety of applications. University and industry collaboration initiated a new business of new NDE for health monitoring and diagnostics.