Structural Health Monitoring (SHM) Using Strain Gauges, PVDF Film and Fiber Bragg Grating (FBG) Sensors: A Comparative Study

The term Structural Health Monitoring has gained wide acceptance in the recent past as a means to monitor a structure and provide an early warning of an unsafe condition using real-time data. Utilization of structurally integrated, distributed sensors to monitor the health of a structure through accurate interpretation of sensor signals and real-time data processing can greatly reduce the inspection burden. The rapid improvement of the Fiber Bragg Grating sensor technology for strain, vibration and acoustic emission measurements in recent times make them a feasible alternatives to the traditional strain gauges transducers and conventional Piezoelectric sensors used for Non Destructive Evaluation (NDE) and Structural Health Monitoring (SHM). Optical fiber-based sensors offers advantages over conventional strain gauges, PVDF film and PZT devices in terms of size, ease of embedment, immunity from electromagnetic interference(EMI) and potential for multiplexing a number of sensors. The objective of this paper is to demonstrate the feasibility of Fiber Bragg Grating sensor and compare its utility with the conventional strain gauges and PVDF film sensors. For this purpose experiments are being carried out in the laboratory on a composite wing of a mini air vehicle (MAV). In this paper, the results obtained from these preliminary experiments are discussed.