平板的ANSYS声学分析

平板的声学分析Lordtomorrow一、参数说明板的总体尺寸为0.2*0.2*0.004m。为了求解方便，本次分析采用了板的一半即0.2*0.1*0.004m进行谐响应分析，在板的上部中心位置施加1000N的力，频率范围为530－540Hz。对此平板模型进行模态分析，其结果如表1所示：表1平板模态分析阶数频率（Hz）1536.032658.0931447.441487.952195.2二、有限元模型图1平板模型图2空气介质模型三、网格划分图3整个模型的网格划分四、结果与分析图4空气介质在平板振动频率为531Hz时的声压分布图5空气介质在平板振动频率为534Hz时的声压分布图6空气介质在平板振动频率为536Hz时的声压分布图7空气介质在平板振动频率为538Hz时的声压分布图8空气介质在平板振动频率为540Hz时的声压分布经ANSYS求解，得到了表2所示的声压最大值和最小值，其内部具体的分布情况如图4至图8所示。表2声压分布频率（Hz）声压最大值（dB）声压最小值（dB）531168.84866.019532171.08268.143533174.01170.998534178.32875.278535186.93283.884536190.6287.611537179.81276.877538175.22472.398539172.29569.608540170.15167.632声压最大值165170175180185190195530531532533534535536537538539540541频率（Hz）声压（DB）图9声压最大值随频率的变化声压最小值60657075808590530531532533534535536537538539540541频率（Hz）声压（DB）图10声压最小值随频率的变化从图9中可知，声压的最大值趋势中的最大值出现在536Hz附近，与平板的一阶模态536.03Hz相一致；同理，图10中声压最小值分布趋势中的最大值也出现在536Hz附近，可知，平板的振动频率达到它的固有频率时振动最大，从而使得其产生声压最大。程序清单---------------------------------------------------------------------------------/PREP7ET,1,SOLID45!壳单元类型1ET,2,FLUID30!acousticfluidelementwithux&uy(0-Structurepresentatinterface(unsymmetricelementmatrix))ET,3,130!acousticinfinitelineelementr,3,0.3,0,0ET,4,FLUID30,,1,0!acousticfluidelementwithoutux&uy(1-Nostructureattheinterface(symmetricelementmatrix))!materialproperties!材料1为铁MP,EX,1,2.1E11MP,DENS,1,7800MP,NUXY,1,0.3!材料2为空气介质MP,DENS,2,1.21MP,SONC,2,344!建立模型wprot,0,-90,0SPHERE,,0.3,0,180!SPHERE,RAD1,RAD2,THETA1,THETA2wprot,0,90,0BLOCK,0,0.1,-0.002,0.002,-0.1,0!BLOCK,X1,X2,Y1,Y2,Z1,Z2BLOCK,-0.1,0,-0.002,0.002,-0.1,0VGLUE,2,3VOVLAP,1,2!OverlapsvolumesVOVLAP,3,4!对编号为2的体划分网格lesize,9,,,20,1lesize,19,,,20,1lesize,14,,,20,1lesize,18,,,20,1lesize,11,,,20,1lesize,16,,,20,1lesize,12,,,20,1lesize,17,,,20,1lesize,8,,,4,1lesize,15,,,4,1lesize,13,,,4,1lesize,10,,,4,1VSEL,s,,,2VATT,1,,1mshkey,1!Specifieswhetherfreemeshingormappedmeshingshouldbeusedtomeshamodel.1—Usemappedmeshing.VMESH,2alls!对编号为4的体划分网格lesize,32,,,20,1lesize,31,,,20,1lesize,35,,,20,1lesize,33,,,20,1lesize,28,,,20,1lesize,34,,,20,1lesize,20,,,4,1lesize,27,,,4,1VSEL,s,,,4VATT,1,,1mshkey,1!Specifieswhetherfreemeshingormappedmeshingshouldbeusedtomeshamodel.1—Usemappedmeshing.VMESH,4alls!对编号为1的体划分网格(此步骤划分网格需要手动进行)VSEL,s,,,1VATT,2,,2!指定的材料属性为空气介质(与结构耦合)SMRT,1VMESH,1alls!修改不与平板（结构）接触单元的材料类型类型为空气介质（不与结构耦合）esel,s,type,,1nsle,sesln,s,0nsle,sesel,invensle,semodif,all,type,4alls!在边界生成吸收单元。（使用单元fluid130）Asel,s,,,1,2NSLA,S,1type,3real,3mat,2esurf!Generateselementsoverlaidonthefreefacesofexistingselectedelements.alls!建立流－固接触面Asel,s,,,8Asel,A,,,10Asel,A,,,7Asel,A,,,5Asel,A,,,19Asel,A,,,15Asel,A,,,17Asel,A,,,20NSLA,S,1esel,s,type,,2sf,all,fsi,1alls-------------------------------------------------------------------------------------------------------!第一种后处理方式，得到空气介质的声压分布，单位为分贝/soluantype,harmichropt,fullf,131,fY,1000.allsnsubst,10kbc,1HARF,337,337!加载80Hz的频率SOLVE!对与结构耦合的空气单元和未与结构耦合的空气单元进行后处理，得到声压分布/post1SET,FIRSTesel,s,type,,2esel,a,type,,4PLESOL,NMISC,4,0,1.0-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------!第二种分析后处理方式，!使用谐波分析法对530－540Hz频率之间进行频率扫描计算第一阶弯曲模态，从而检测到结构模型的固有频率/soluantype,harmichropt,fullf,131,fY,1000.allsnsubst,10kbc,1HARF,530,540!加载频率530－540SOLVE!检测到结构模型的固有频率/post26plcplx,0nsol,2,1,u,x,d1uxstoreconjug,3,2prod,4,2,3sqrt,5,4*get,uxmx,vari,5,extrem,tmax/COM-------------------------------------------------------------/COMExpectedResult:/COM/COMThefollowinguxmxshouldequal/COM-------------------------------------------------------------*status,uxmxfinish