A fundamental study on an application of a mechanism of metamaterials to a solid wave.

(a vibration isolation device by using rotational inertia damper)

Abstract

This paper shows a fundamental study to apply the principle of metamaterial to solid waves. A method of making the stiffness apparently negative and an effect of the apparently negative stiffness for a lumped parameter system in which the governing equation is isomorphic to the central difference approximation formula of the wave equation are investigated from the viewpoint of vibration isolation. The results are as follows: 1) It was shown that the stiffness of the mass/spring system can be made apparently negative by using a rotational inertia damper. 2) By inserting a system with apparently negative stiffness between the excitation source and the target, the system acts as a high-cut filter and reduces the input from the excitation source to the target. 3) It was shown that the cutoff frequency and cut level of the high-cut filter can be controlled independently by the rotational inertia of the rotational inertia damper and the degrees of freedom of the system whose stiffness is apparently negative.