Waveguide metamaterial rod as mechanical acoustic filter for enhancing nonlinear ultrasonic detection

Nonlinear ultrasonic guided waves are among the most promising new tools for early stage damage detection owing to their high sensitivity and long-range propagation features. However, signatures from instrumentation, transducers, couplant effects create false positives mixing with material- or defect-induced nonlinearities, leading inaccurate measurements. Here, we propose a novel technique using waveguide metamaterial rod, which acts as mechanical acoustic filter suppression of higher harmonic components in measured signal. The proposed consists an array flat axisymmetric ridges arranged periodically on surface rod. It is experimentally demonstrated that filtered when rod placed at transmission side, thus removing unwanted nonlinearities received signal pitch-catch configuration. Furthermore, application this method by detecting discontinuity workpiece through its nonlinear response enhanced metamaterial. This attractive material diagnosis engineering, biomedicine, health monitoring critical engineering assets.