Intelligent structural health monitoring (SHM) of composite aircraft structures using acoustic emission (AE) sensors

Abstract

The objective of this paper was to present initial results from a new project aiming to develop an intelligent system to monitor the health of carbon fibre reinforced plastics (CFRP) in aircraft structures using Acoustic Emission (AE) technology. Structural Health Monitoring (SHM) is a relatively new method in the aircraft industry of monitoring the condition of a structure in real time while the structure is in service. A SHM system could make some regular inspections unnecessary and allow maintenance only when required. Especially for composite aircraft structures where the incidence of fatigue is low, this technique could potentially be economical and improve the safety of the structures. This paper shows that AE is an appropriate technique to monitor the health of composite materials online. AE is sensitive to micro cracks even before most other Non-Destructive Testing (NDT) techniques can detect them. It is possible to determine the location and the type of defect (delamination, matrix cracks, fibre breaks) in the structure to a certain degree. Also the overall AE activity increases significantly towards the end of the life of the structure.