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1、江蘇大學(xué)碩士學(xué)位論文微穿孔板吸聲結(jié)構(gòu)的吸聲性能及其優(yōu)化姓名:祝瑞銀申請學(xué)位級別:碩士專業(yè):環(huán)境工程指導(dǎo)教師:趙曉丹20070601江蘇大學(xué)工程碩士學(xué)位論文摘要本文根據(jù)馬大猷教授的微穿孔吸聲理論,討論了微穿孔板吸聲結(jié)構(gòu)的基本特性。計算研究了單層微穿孔板吸聲結(jié)構(gòu)的吸聲系數(shù),影響微穿孔板吸聲結(jié)構(gòu)吸聲性能的參數(shù)主要有穿孔孔徑、板的厚度、穿孔率及空腔深度。通過理論計算和實驗數(shù)據(jù)對這些參數(shù)進行分析,得到微穿孔板的吸聲特性:穿孔率小對獲得高的穿孔吸聲系數(shù)有利,穿孔率不宜超過4%;在條件容許的情況下,背腔深度宜盡可能大,對提高低頻的吸聲系數(shù)有利;孔徑則是以盡可能小為好;選用較厚的板也可以提高吸聲系數(shù)
2、。進一步對雙層微穿孔板結(jié)構(gòu)進行了研究.在單層微穿孔板計算方法的基礎(chǔ)上,進行了雙層微穿孔板吸聲系數(shù)的計算,與單層微穿孔板進行了比較,說明了雙層結(jié)構(gòu)研究的重要性。應(yīng)用遺傳算法對其結(jié)構(gòu)參數(shù)進行了優(yōu)化,結(jié)果表明,雙層微穿孔板在經(jīng)過遺傳算法優(yōu)化之后,在所選頻率范圍內(nèi)能夠獲得飽滿的吸聲系數(shù)曲線,與未優(yōu)化的雙層結(jié)構(gòu)相比,吸聲性能有了顯著的提高,不僅得到了高的吸聲系數(shù),而且吸聲頻帶也相應(yīng)加寬,通過實驗也驗證了理論計算的正確性。為實際工程應(yīng)用提供了理論基礎(chǔ)。關(guān)鍵詞:噪聲控制;微穿孔板;吸聲系數(shù);遺傳算法;優(yōu)化設(shè)計。江蘇大學(xué)工程碩士學(xué)位論文ABSTRACTBasedonMaDayou'smicro-pe
3、rforatedpanelabsorbingtheory,thisthesisdiscussedthefundamentalpropertyofmicro—perforatedpanelabsorber.Theparametersthataffecttheabsorptioncharacteristicsofmicro-perforatedpanelaletheperforation-aperture,thethicknessofperforatedpanel,theperforationarearatioandthedepthofthecavity.Theseparametersh
4、avebeenanalyzedbytheoreticalcalculationandtheresultofexperiment.Thefollowingabsorptivecharacteristicsofmicro-perforatedpanelabsorberhavebeenfound.Itisbenefittoselectanduselessperforationrateandtheperforationrateusuallyshouldbenotmorethan4%.Underthepossibleconditionitisbettertoselectthelongdepth
5、ofthecaVitywhichishelpfultoimproveabsorptioncoefficientinlowfrequency.Inusualtheperforation-apertureshouldbeassmallaswhichitcanbemachined.Usingthickermicro—perforatedpanelisalsobenefitforgettinghigheracousticsabsorptioncoefficient.Further,doublelayermicro—perforatedpanelstructureisresearched.Ma
6、kingUSeofthesinglelayermicro—perforationpanelreckoning,theacousticsabsorptioncoefficientofdoublelayermicro-perforatedpanelstructureiscalculated.Comparingwithsinglelayermicro-perforationpanel,doubMlayermicro-perforatedpanelstructurehashigheracousticabsorptionability.Doublelayermicro-perforatedpa
7、nelstructureisresearchedtobeopthnizedbytheGeneticalgorithmmethod.Itisnotedthatafteroptimizationdoublelayermicro-perforatedpanelstructurec孤getmoresatisfactoryabsorptioncurve.ItsacousticscharacteristicshavebeimprovedaloLbothinitsaco