An artificial neural network methodology for damage detection: Demonstration on an operating wind turbine blade

This study presents a novel artificial neural network (ANN) based methodology within avibration-based structural health monitoring framework for robust damage detection.The ANN-based methodology establishes the nonlinear relationships between selecteddamage sensitive features (DSF) influenced by environmental and operational variabilities(EOVs) and their corresponding novelty indices computed by the Mahalanobis distance(MD). The ANN regression model is trained and validated based on a reference state (i.e.,a healthy structure). The trained model is used to predict the corresponding MD of newobservations. The prediction error between the calculated and predicted MD is used as anew novelty index for damage detection. Firstly, an artificial 2D feature set is generatedto illustrate how the limitations of solely using the MD-based novelty index can beovercome by the proposed ANN-based methodology. Secondly, the methodology is imple-mented in data obtained from an in-operation wind turbine with different artificiallyinduced damage scenarios in one of its blades. Finally, the performance of the proposedmethodology is evaluated by the metrics of accuracy, F1-score and Matthews correlationcoefficient. The results demonstrate the advantages of the proposed methodology byimproving damage detectability in all the different damage scenarios despite the influenceof EOVs in both the simulated and real data