Efficient structural health monitoring using sparse distributed sensor array
This is a joint project with Dr Paul Wilcox at University of Bristol. Structural Health Monitoring (SHM) has the potential to radically alter the way in which safety-critical structures, such as aircraft fuselages, ships’ hulls and power plant, are designed, operated and maintained over their lifetimes. One of the popular ideas for plate-like structures is to use guided waves (Lamb waves) which propagate in the plates and so can cover large areas. Previous research has shown the potential for this idea, important progress being made for example in the areas of transduction and communication, but the ideal of producing a map of defect locations for a large area using a small number of transducers remains a challenge. The goal of this proposed work is to demonstrate that an SHM system based on the transmission of low frequency ultrasonic guided waves between elements in a sparse distributed array of permanently attached sensors can be used to provide reliable damage detection and location capability throughout a structure. The key new features here are: (a) the use of a new intelligent subtraction algorithm, in which recorded images are subtracted from a reference (undamaged) image, so dramatically increasing the imaging capability from a given number of sensors; (b) the use of low frequency Lamb waves, with optimisation of mode and frequency, to image structures which include some realistic complexity, such as stiffeners. The Imperial work is concentrating on low frequency transduction and developing reliable ways of extracting the key features from the received signals. You can view a presentation here.
NDE Research Association Ltd
Cicero, T., Cawley, P., Simonetti, F. and Rokhlin, S.I. 'Potential and Limitations of a Deconvolution Approach for Guided Wave Structural Health Monitoring', Structural Health Monitoring, Vol 8, pp381-395, 2009.
Clarke, T., Cawley, P., Wilcox, P. and Croxford, A.J. 'Evaluation of the damage detection capability of a sparse array guided wave SHM system applied to a complex structure under varying thermal conditions', IEEE Trans UFFC, Vol 56, pp2666-2678, 2009.
Clarke, T., Simonetti, F. and Cawley, P. 'Guided wave health monitoring of complex structures by sparse array systems: Influence of temperature changes on performance', J Sound and Vibration, Vol 329, pp2306–2322, 2010.