二维声子晶体带隙的栅板调节作用分析

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1、瓣j：麓●rJ-睡霉煎篇崩中南大学硕士论文ABSTRCTArrangedintwo—dimensionaliron／watersquarephononiccrystalplateforthemotherboardmodel，weanalyzetwo—componentgridplate，three-component酣dplateaswellasgridplatewithdefectsonthemotherboardacousticpermeabilitywithfinitedifferencetimedomain(FDTD)，D

2、etailsareasfollows：1，Thefillrateofthegridplate，gridplaterelativetothelocationofthemotherboard，thethicknessofthegridplate，gridplatescattererswithinthecinse—packedstructurewillaffectthemotherboardacousticpermeability．nlegridplatescattererswithintheclose-packedstructuret

3、hanthefillrateofthegridplate，gridplaterelativetothelocationofthemotherboard，thegateplateitself,thethicknessoffactorsshouldbelarge．Close—packedstructureofthegridplateCangreatlyaffectthemotherboardsoundpermeability，andevenhigh-frequencybandgap；largefillingratioofthegate

4、platesmallerfillingratioofthegridplatestructure；three-tiergridplatethanthesinglelayergateboard．2，Twogroupsofstructuralgridplate，鲥dplateofthescatteringbodyhasaverysoftmaterial．usually1cadtothemotherboardwithabandgapstructureinthelowfrequencyrange；threegroupscladdingsys

5、tem，suchasrubber(1ead)／water，rubber(ironwillleadtolow-frequencybandgap)／waterandrubber(air)／waterandother’hard’core‘soil'typeofcladdinggridplate，corecolumnmaterialofthistypeofsystemofscatterersisrelativelysmallbandgap；threegroupselementcladdingsystemssuchaSlead(rubber

6、)／water，iron(rubber)／waterandair(rubber)／waterandother。soft'core’hard’typeofcladdinggridplate，theouterlayerof’hard’materialsdominatethescatteringeffectof；’hard’core’soft’veneercladdingand’soft’core’hard’claddingveneermixedsystem，therewillbeabandgapofthestackeffect，and

7、littlerelationshipwiththembeforeandallertheorderoftheveneercombination．3．Thethicknessofthegridplateadjustmentofthebandgapofphononiccrystalsmotherboardsgenerallyhaveenhancedtheeffectandthiseffectisrelatedwiththeformationofthebandgapprinciple．Amongthem，threesetsof舒dplat

8、esystemwithlocallyresonantstructures，withtheincreaSeinthenumberoflayersofthegridplate，thethickness中南大学硬士论文increases，thelow丹e