Guided wave propagation modelling to aid understanding of acoustic emission system performance on complex aerospace structures
Abstract »The performance of Acoustic Emission (AE) systems is modelled using the linear time-invariant systems approach. This is done to aid the understanding of how AE systems perform on real aircraft structure. The motivation for this is to improve the understanding of AE results from current structural tests and to inform future AE system design.
The focus of the work is to model the propagation of ultrasonic guided waves across features that are present in typical aircraft structure. Wave propagation has a large influence on the performance of an AE system yet is either not considered or only considered simply in many industrial tests. An empirical model for propagation across an L-section bolted to a plate has been created from experimental results for a range of incident angles. The bolted L-section is a simplification of stringers which are a common feature on aircraft structure.
The accuracy of the feature model is assessed; first with experimental results from a plate with 2 bolted L-sections and then with experimental results collected from a section of A320 wing skin with real stringers. Regions where the model predicts sensitivity to AE events above that of the experimental results are found and the implications of these regions for system design are discussed.
The feature model is included in an overall model of an AE system which includes realistic models of AE events. Example results from the overall model are used to show the affects of system parameters and processing algorithms from a real AE system on system performance. These examples show the benefits and limitations of this modelling approach.
Biography: Mark is enrolled upon the UK Centre for Doctoral Training in Non-destructive Evaluation’s Engineering Doctorate program, based at the University of Bristol and Airbus Operations Ltd. His research interests include the long term performance of guided wave structural health monitoring systems and how complex geometries, typical of real aerospace structures, affect acoustic emission system performance.
Affiliation: University of Bristol Mechanical Engineering BS8 1TR Bristol United KingdomCroxford, Anthony J.Croxford, Anthony J.
Affiliation: University of Bristol Bristol United KingdomAtherton, KathrynAtherton, Kathryn
Affiliation: Airbus Operations Ltd Bristol United Kingdom*Contact