关键词: 振动与波, 周期结构, 带隙结构, 传递矩阵法, 阻抗失配

Abstract: A medium with periodic heterogeneity has special frequency ranges in which waves may be either effectively attenuated or allowed to propagate in space. These frequency ranges are referred to as stop bands (or band gaps) and pass bands (or bands). Such unique characteristics can be employed to design a kind of virtual mechanical filters with periodic structures. The mechanical filter can be inserted between the lower isolator and the base of the raft isolation system to alter the transmission properties from the machine to the base, so that the frequency of the raft isolation system can approach its excitation frequency, and differ from the shells intrinsic frequency and excitation frequency of the cabin. The transmission matrix method is used to analyze the transmission property and the dynamic response of the raft system. Result shows that the responses of displacement, force and power flow of the base can be greatly reduced when the excitation frequency is within the stop bend of the periodic structure.

Key words: vibration and wave, periodic structure, stop bands, transmission matrix method, impedance mismatch