Deformation monitoring by using optical fiber grating sensor

Abstract

Fiber grating sensors have found increasing use in structural applications as deformation monitoring sensors. In the current work, a simple, low cost and fast responding interrogation system that makes use of a hybrid fiber Bragg grating‐long period fiber grating arrangement to achieve intensity modulation has been developed. The system has been used to interrogate short period fiber Bragg gratings (FBG) for dynamic strain monitoring. It has been shown that the current system is capable of resolving strain down to 1.5 μϵ and has successfully monitored high frequency strain variation up to 150 kHz in a PZT actuator. It has also been employed successfully to monitor premature fatigue crack closure.

Key words:

• fiber Bragg grating
• intensity modulation
• strain interrogation
• crack closure measurement

Notes

Corresponding author. (Tel: [phone]; Fax: [phone]; Email: [email protected])