An effective structural health monitoring methodology for damage isolation based on multisensor arrangements

The development of strategies to evaluate health of mechanical structures has been studied by the international community due to their potential application in the prevention of failures and optimization of maintenance procedures. These systems requires digital signal processing algorithms and interpretation methods, which aim to extract parameters sensitive to the rise of discontinuities in the material from measurements, to classify signal events to detect the damage onset. This paper proposes a simple and effective methodology for monitoring the integrity of mechanical structures, based on Lamb wave and pitch-catch approach, through analysis of signals generated by multisensor arrangements. These signals are processed by discrete wavelet and Hilbert transform, intended to improve peak amplitude estimation, through noise and dispersion reduction. Assessment of structure's integrity proceeds through the joint analysis of damage indices calculated from the discrepancy of the maximum amplitude of the signal measured by each sensor of the arrangement. Experimental application of the method to an aluminum plate showed its effectiveness to detect, localize and evaluate damage severity in established regions of the monitored area, including the case of two simultaneous damages.