Temperature-controlled tunable zigzag metamaterial beams to manipulate flexural waves

The study of artificially structured materials to control waves is ongoing, owing to their unprecedented properties. However, their narrow working frequency ranges significantly hinder their applications. In this study, a kind of tunable zigzag metamaterial beams with wider working frequency ranges are proposed by incorporating springs and damping elements into our previously proposed pure zigzag beams. The complex band structures of these tunable zigzag metamaterial beams are characterized by the spectral element method (SEM), and a parametric analysis of spring rigidity and damping is conducted. The results show that the full stopbands of our tunable zigzag metamaterial beams are highly sensitive to spring rigidity, which confirms their good tunability. Actuators serving as spring and damping elements are then designed and 3D printed using a thermally sensitive material, VeroPureWhite. The actuators are glued to pure zigzag aluminum beams to generate integrated tunable zigzag metamaterial beams. The transmission spectra are measured for the integrated tunable zigzag metamaterial beams under several thermal loading cycles. Both the numerical and experimental results demonstrate the wide tunability of our proposed tunable metamaterial beams.