A study on the isolation performance of trichiral lattices with gradient geometry

This paper investigates the vibration transmission and isolation performance of the trichiral structures with uniform and gradient geometry parameter. The method combining Bloch's theorem and the finite element method (FEM) are applied to study the dispersion characteristic of the trichiral structure. The effect of geometry parameters on the distribution of the band gap is analyzed. On this basis, a trichiral structure with gradient geometry parameters is presented and FEM is exploited to evaluate the dynamic response under the harmonic excitation. The results demonstrate that vibration transmission displays significant attenuation in the frequency range corresponding to the band gap. The distribution of the band gap is determined by the cell parameters and can be tuned to any desired frequency range. The harmonic response analysis suggests that a gradual variation in cell size distribution makes the structure realize vibration suppression in a wider frequency band, which cannot be achieved by the uniform structure.