Vibration isolation by novel meta-design of pyramid-core lattice sandwich structures.

Pyramid-core lattice sandwich structures (PCLSSs) have been widely used in various engineering fields due to their high stiffness-to-density ratio. Although the advantages of such structures are obvious, the rather poor vibration isolation property restricts their applications. In the present work, we develop the chessboard-designed and gradient PCLSSs in order to improve their out-of-plane vibration isolation performance. The numerical results are obtained by the finite element method (FEM). Our results show that the chessboard-designed PCLSS has a lower and wider band-gap for the out-of-plane vibration than the classical PCLSS. The effects of the geometry and material parameters on the band-gap are analyzed. A gradient PCLSS with the core radius varying linearly is proposed. Compared to the classical PCLSS, the gradient PCLSS can expand the frequency range of the band-gaps significantly while maintains the high stiffness-to-density ratio. Moreover, the spatial gradient of the pyramid-core is utilized to realize the rainbow trapping and the nonreciprocal transmission of the elastic flexural waves. The novel meta-designed PCLSSs show potential applications where both a good vibration isolation and a high stiffness-to-density ratio are needed.0 [ABSTRACT FROM AUTHOR]