The Research On Sound Insulation And Noise Reduction Based On Periodic Structure Slabs

Vibration and noise widely exist in the fields of construction, machinery andaviation, the suppression of harmful noise and vibration has become an urgent problemto be solved in the engineering technology. Solid structure is a major media ofvibration transmission, in which vibration can propagate in long distance with lowattenuation, so the control of noise and vibration in the solid structure is generallyconcern. The isolation of noise and vibration in their pipeline utilizing periodiccomposite structure is a new way for the solution of this problem. Periodic compositestructure has band gaps of elastic wave or acoustic wave, that is to say, the propagationof elastic wave or acoustic wave in band gaps is prohibited. This property of periodiccomposite structure provides new prospects for the solution of vibration and noisereduction in engineering practice.Based on the research status and basic theory of periodic composite structure, thecharacteristics of band gaps and the performance of sound insulation and noisereduction of periodic composite structure slabs are studied, and the feasibility for noiseand vibration control in engineering structures is presented. The main work is shown asfollowing:(1)Using the plane wave expansion, the band structures of the basic unit ofperiodic composite structure slabs are studied, and the results are evaluated againstthose by the finite element method.(2)Based on the basic unit, the impact of the structural parameters on the positionand width of the band gap is studied by modulating filling factor and other structuralparameters of periodic composite structure slabs.(3)The calculation methods of propagation characteristics of the one-dimensionalperiodic structure with infinite period and finite period are studied, and the feasibilityof the slabs for sound insulation and noise reduction is discussed.(4)Based on the calculation and analysis of the transmission characteristic curveof the periodic structure slabs with finite length, the impact of the number of cyclesand filling factor on sound insulation performance is discussed, and the impact of thestructure parameter on vibration isolation through the displacement field of plates isstudied. The results show that such composite plate structures can adjust the positionof band gaps, increase the degree of attenuation and has a good sound insulation and noise reduction effect by the reasonable modulation and collocation of parameters ofperiodic structure slabs.