Case Study 2010-2012. Research Project MACH

'MACH' Monitoring of Aircraft Component Health - Fibre Laser Acoustic Emission Structural Health Monitoring Project

Dates: May 2010 to December 2012 (31 Months)

Sponsors: South East England Development Agency (SEEDA)

Project Brief:

The objectives of the project are to develop a fibre optic based acoustic emission system suitable for deployment in an in-service aircraft environment and to demonstrate the capabilities of the system on components representative of actual aircraft structure. This builds on the initial multi-channel fibre laser system developed and demonstrated in the HealthMaP programme.

The outputs from this MACH project will be a hardware/software package, which provides a stable and reliable acoustic emission system using fibre lasers as the sensing devices. This will include a demonstration of the system on a suitable test opportunity.

Fibre laser sensors offer the potential for composite structures with embedded structural health monitoring.  For aluminium aircraft visual inspection is used to monitor damage, but this is not possible for composite structures where, for example, delamination can occur without any indication of damage on the surface. This project aims to move the technology to TRL5.

Partners:

Smart Fibres Ltd, QinetiQ Ltd (www.qinetiq.com)

Resolution:

Delivered: Development and demonstration of hardware and processing algorithms with capability to detect acoustic emission events and compute their position to within 25 mm of the transmitted source.

Below is a video of data collected from the demonstration hardware during a test. The green points on the right show the repeatability of readings from stimuli at positions on a 0.1 mm grid. The blue points show the fibre laser sensor locations.

The top waveform shows the raw acoustic signals picked up at each sensor location, whilst the lower waveform shows an FFT trace for each sensor.