COMPUTATIONAL MODELLING OF GUIDED WAVE PROPAGATION FOR ICE DETECTION ON COMPOSITE MATERIALS

Övrigt konferensbidrag, 2016

Guided waves are an efficient non-destructive tool in inspection and fault detection of elongated structures. Due to the special characteristics of composite materials, study of guided wave propagation in them has been an interest. Icing condition is a well-known problem in wind turbine industry and in this work application of guided wave propagation for ice detection on composite materials is studied. A 3D shell model is developed in which ice is placed on the plate by changing the properties of specific elements in the icing region. The excitation is applied to the middle of one side of the plate with a low angle of inclination and the centre frequencies varying from 3 kHz to 7 kHz. The signal is received in 24 nodes equally distributed on the plate known as the measurement nodes. The model with a patch of ice is validated using a 3D solid model in which ice is placed as a second solid layer. Comparison shows the model can be simplified using this method without significant change in the results. The Baseline Signal Stretch with the mode decomposition method is applied to the model for temperature variations. Effects of ice accretion on a composite plate is studied in time, frequency and wavenumber domains. In each case post-processing approaches are introduced for this specific application. Moreover, icing index is introduced which is sensitive to accumulated ice on the plate. The model is calibrated and final results are validated using an experimental work which is performed in a cold climate lab. Using the model and introduced criteria both thickness and location of ice on the plate are identified. All the results show that application of guided waves is a promising and accurate tool in ice detection on composite plates.