Prestress-controlled asymmetric wave propagation and reciprocity-breaking in tensegrity metastructure

In this letter, prestress is harnessed to break the spatial or/and time wave reciprocity and realize asymmetric elastic wave propagations in the full elastodynamic context. Unlike other asymmetric wave systems that rely on the complicated microstructures or multi-physical coupling, the proposed metastructure is simply constructed with repetitive prismatic tensegrity cells (PTCs) where prestress exists intrinsically. By investigating the prestress-trigged wave mode selection and conversion phenomena with a theoretical model, we developed a new approach to achieve asymmetric elastic wave propagation in the metastructure with modulated prestress distribution in space. Furthermore, by expanding the prestress tuning in both space and time domains, the elastodynamic reciprocity is finally broken in the tensegrity metastructure without introducing nonlinearity or external bias fields to the system. Due to the simple construction and intrinsic tunability, the proposed tensegrity metastructure design can be potentially useful in various applications, such as vibration isolation and elastic wave communication.