An investigation of effective detection length of a localized micro-failure in a laminated thin composite plate using FBG sensor integrated AE system

摘要

In recent years, there is a growing demand in developing FBG-AE system for Structural Health Monitoring (SHM) systems for fibre composite structures. The excellent static and dynamic strain measuring capabilities of Fibre Bragg Gratings (FBG) sensors are attributed to the major reason for replacing conventional Acoustic Emission (AE) sensor heads with FBG sensors. In addition, the physical size of FBG sensor provides greater access to embed them in composite structures without affecting mechanical properties of the composite significantly. This research work has investigated the direction dependency of the sensor and the effective length of the sensor from the source location for the use of FBG - AE systems in damage detection of thin composite plates. Besides, the sensitivity of embedded FBG sensor in composite laminates also investigated during this study. It has been seen that FBG sensor must be located at least 200 mm from the expected failure region in order to acquire optimal from AE sources. This study also successfully detected AE signals from FBG-AE system.