A method is described for the identification of abnormal or unexpected conditions from measured response data. Such a technique would be useful in a wide range of engineering situations where a clear, early warning of an abnormal condition is required, but where classification of the specific abnormality is only of secondary importance. In this work, occurrences of unexpected operating conditions are indicated by measured data which exhibit a high degree of novelty with respect to that corresponding to normal conditions or responses. The proposed approach is based upon the probability density function (PDF ) estimation using a kernel method, the basis of which is described. The need for data compression in practical applications of PDF estimation is highlighted and a method demonstrated which is based on the wavelet transform. The combined data compression and PDF estimation approach for novelty detection is applied to data measured from a gearbox with a progressive fault and to radar data corresponding to six military targets. In both cases, abnormal situations are clearly identified on the basis of novel data inputs.

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An initial design of a morphing wingtip for a regional jet aircraft is developed and evaluated. The adaptive wingtip concept is based upon a chiral-type internal structure, enabling controlled cant angle orientation, camber, and twist throughout the flight envelope. A baseline turbofan aircraft configuration model is used as the benchmark to assess the device. Computational fluid dynamics based aerodynamics are used to evaluate the required design configurations for the device at different points across the flight envelope in terms of lift/drag and bending moment distribution along the span, complemented by panel-method-based gust load computations. Detailed studies are performed to show how the chiral structure can facilitate the required shape changes in twist, camber, and cant. Actuator requirements and limitations are assessed, along with an evaluation of the aerodynamic gains from the inclusion of the device versus power and weight penalties. For a typical mission, it was found that savings of around 2% in fuel weight are possible using the morphing wingtip device. A similar reduction in weight due to passive gust load alleviation is also possible with a slight change of configuration.