Analysis Of The Sound Transmission Loss Of Laminated Composite Plate Structure

The development of Modern Aerospace Industry and Marine Industry have higherrequest for structure strength, vibration, noise and self weight of planes, submarines andships, which caused that composite components like laminated composite plates waswidely put into use. Laminated composite plate was widely applied to Aerospace,Automobile and other transportation fields not only for the characteristics with lightspecific gravity, high specific strength, high specific rigidity and good corrosionresistance, but also for main reason with superior damping and anti-noise features.Therefore, there is an important meaning for noise reduction of laminated compositeplate structure thru research on sound transmission and insulation characteristics theoryof laminated composite plate structure, and let it have more extensive application onthis field. This article is to research on Sound transmission characteristics of laminatedcomposite plate structure.Firstly, fully considering the structure feature of laminated composite plate, thrubuilding laminated plate sound transmission computation model, based on transfermatrix method, combined with elastic mechanics equation of composite materials andacoustic wave equation in solid, sound pressure transmission coefficient formula oflaminated composite plate was achieved, and also the value of sound transmission lossof laminated plate structure was calculated thru sound transmission loss computationmodel.Secondly, analyzing and discussing the effect factor of Laminated plate structure’ssound transmission loss, discussing acoustic wave incidence angle’s affection onlaminated plate sound transmission loss when plane wave come in; under the conditionof diffuse sound field, structure parameters like laminated plate’s laying angle, plate’selastic modulus ratio, plate thickness and density impact on laminated plate soundtransmission loss. It showed that laminated composite plate was affected by the factorslike fiber and matrix’s performance, laying ways and laying angle, so mass law can’tcorrectly response the laminated plate’s sound-insulated capability. The bigger theincidence angle of acoustic wave, the less the sound transmission loss; the larger thethickness of composite plate, the bigger the sound transmission loss; the ratio betweendensity of composite materials and elastic modular of composite materials have no current linear relation with sound transmission loss.Lastly, analyzing the laying angle optimum scheme of laminated plate’s the biggestsound transmission loss thru using simulated annealing algorithm. On the other hand,adopting improved simulated annealing algorithm, different layers number underdifferent frequency determines the best laying angle scheme of composite plate bygetting the biggest sound transmission loss. Through comparison and discussion withmethod of exhaustion, the feasibility and high efficiency of improved simulatedannealing algorithm provides the evidence for structure optimal design of laminatedplate in practical application.