Low Frequency,Broad Band And Light Weight Design For Locally Resonant Phononic Crystal Beams

Beam structures which function as connections or bearings are widely used in support frames,train tracks,bridges,etc.It's proverbial that vibration in machinery that will cause damage both in performance and service life of equipment,not to mention noise pollution and health damage.Through the beam structures,vibration will transmit to other part of the machinery.While vibration transmits,beam structures will also easily get affected and injured.With industrial development,there are more demands for vibration control.Due to different operating condition,vibration which appeals to be different forms will add difficulties in controlling,especially in low-frequency.Recently,the ideal of vibration control is switching from governance to design.In the area of condensed matter physics,Phononic Crystals(PCs)show a new approach to solve this problem.Phononic Crystals are periodic composites or structures that consist of two or more materials.The characteristics of band gaps(BGs)come from periodicity in PCs.Band gaps can be utilized to manipulate the wave propagation in structures.Especially locally resonant PCs have extensive application prospects in low frequency vibration control.But there are limits in the fields of low frequency,broad band,and light weight.Based on PCs theory,combining with mass amplification theory and metadamping theory,this paper has studied characteristics of BGs in locally resonant beams.The main findings and inclusions of this literature are given as follows:1.Based on multibody modeling and simulation,using multibody hinge simulation and Bloch theory,a unit designing method which could be used in calculating BGs in multibody structures is studied.2.A Mass amplification structure which can generate low frequency BGs with light added mass is designed to control low frequency vibration.Two different supporting conditions(supported on ground and supported ion beam)are considered and studied.The effect of different leverage ratio on characteristics of BGs are studied.Finally,an experiment is designed to prove the theory.3.A metadamping locally resonant structure is designed to widen the band gaps.Combining with metadamping theory,a X shaped structure which can meet the demands of low frequency and broad band is designed.The dynamical characteristics of unit are deduced.The characteristics of metadamping are revealed.By using finite element simulation software and multibody physics module,metadamping phenomenon and the characteristics of BGs are revealed.Parametric influence has also been studied.In conclusion,a research about the low frequency,broad band and light weight design of locally resonant beams is made in this paper.The characteristics of BGs are revealed.This article provides a new design ideal and technical support for low frequency vibration control in beam structures.