Papers by Author: Daley Chetwynd

Abstract: This work was conducted as part of the European Union project ARTIMA and it investigates the potential for a dual use active constrained layer damping treatment for both vibration control and structural health monitoring. It examines a curved aluminium plate with an ACLD treatment formed by mounting a large piezoceramic patch with Araldite 2027. The plate was investigated by ultrasonic Lamb waves generated by the patch, and several smaller piezoceramic transducers were used as sensors. Damage was simulated by adding incrementally increasing saw cuts to the plate, and the technique of outlier analysis was used to classify when this damage had occurred.

Abstract: This work was conducted as part of the European Union project ARTIMA and it investigates the effectiveness of wavelets in damage detection. It examines whether a prior wavelet decomposition of Lamb wave responses facilitates the classification of structural damage. The structure in question is an aluminium plate with viscoelastic-mounted transducers, and the damage took the form of saw cuts on the plate. The novelty detection technique of outlier analysis was used to classify the damage.

Abstract: This paper considers the performance of radial basis function neural networks for the purpose of data classification. The methods are illustrated using a simple two class problem. Two techniques for reducing the rate of misclassifications, via the introduction of an “unable to classify” label, are presented. The first of these considers the imposition of a threshold value on the classifier outputs whilst the second considers the replacement of the crisp network weights with interval ranges. Two network training techniques are investigated and it is found that, although thresholding and uncertain weights give similar results, the level of variability of network performance is dependent upon the training approach