207 / 2021-03-31 22:36:53

Tunable band gap and waveguide of periodic grid structure by thermal control

Tunable;,grid structure,thermal control

Acoustic metamaterials and absorbing materials

In the present paper, a type of lattice structure consist of homogenous but thermal sensitive material, periodically adhered with a series of metallic films acting as local heat sources which generates periodic thermal fields within the lattice structures was proposed. Local change of elastic modulus triggered by periodic thermal fields can be applied to manipulate the band structure and waveguide of such lattice structure. Therefore, a thermal-mechanical coupling model based on finite element method via commercial software is employed to obtain the dispersion curves and the transmission spectrum of in-plane wave propagation. Numerical results for band gaps, which are validated by in-plane wave transmission spectrum also obtained by thermal-mechanical coupling model, shows that band gaps significantly shift to lower frequency zone as the injected heat flux increases. Band width and locations of band gaps can be effectively manipulated by controlling the periodic thermal fields. More than that, it is possible the waveguide can be turned on or off at different frequencies by changing the thermal fields. This paper may pave theoretical foundation for applications of lattice structures in areas such as acoustic switches, vibration isolation, filters and shock absorbers.