Ultrawide stop band in a 3D elastic metamaterial with inertial amplification mechanisms having cross flexure hinges

Abstract

Inertial amplification is a new method to obtain phononic band gaps in peri odic structures. The aim in this thesis is to obtain an ultrawide stop band in three dimensions by using inertial amplification mechanisms. In order to be used in three dimensions, a two stage remote center flexure mechanism design that allows bending in two orthogonal axes is added to the ends of the inertial amplification mechanism. Moreover, cross flexure hinges that prevent undesired torsional, in-plane and out-of plane bending modes of the inertial amplification mechanism are utilized in order to maximize the stop band frequency range. An octahedron structure is formed with this mechanism, which is also used as the building block of a 3D periodic structure. It is shown that a wide stop band can be achieved with the use of cross flexure hinges and a two stage remote center flexure mechanism. By making design and dimensional changes on the mechanisms forming the octahedron, the stop band of the octahedron is widened. Finally, the stop band is maximized by optimizing the thicknesses of the flexures in the inertial amplification mechanisms.