Temperature controlled quasi-zero-stiffness metamaterial beam for broad-range low-frequency band tuning

Despite their engineering significance, locally resonant metamaterials are facing the challenge to cope with the need for broad-range band gap adjustment at low-frequencies. To tackle this problem, this study proposes using shape memory alloys (SMAs) to achieve temperature-controlled quasi-zero-stiffness (TC-QZS) metamaterial beam, which entails tunable and low-frequency band gap through ambient temperature changes. The basic configuration of the proposed TC-QZS resonator embraces a negative mechanism, steming from an SMA and a nonlinear geometrical structure. The stiffness of the positive stiffness mechanism can be effectively neutralised by the negative one, and the neutralisation can be adjusted based on temperature change applied to the SMA. The resultant stiffness variation yields broad-range tunability of the resonant frequency of the TC-QZS resonator. The band gap structure of the metamaterial beam is obtained using the transfer matrix method and verified by numerical simulation. Effects of dominant parameters on band gaps are scrutinized. Results show that the frequency range of the band gap can be continuously tuned from 26 to 69 Hz. This study provides guidance for the realisation of band gap tunibility over a wide frequnecy range and lays the groundwork for the development of elastic wave manipulation and vibration isolation.