一個(gè)采用Ansys分析平板聲學(xué)問(wèn)題的實(shí)例分享

一個(gè)采用Ansys分析平板聲學(xué)問(wèn)題的實(shí)例分享本文對(duì)平板進(jìn)行諧響應(yīng)分析，在板的上部中心位置施加1000N的力，頻率范圍為530-540Hz，并求得其聲壓分布。結(jié)果表明，在共振區(qū)域引其振動(dòng)劇烈所以聲壓較大，符合事實(shí)。本文附有源程序，不過(guò)有些地方需要手動(dòng)操作一下(其中已說(shuō)明)。一、參數(shù)說(shuō)明板的總體尺寸為0.2*0.2*0.004m。為了求解方便，本次分析采用了板的一半即0.2*0.1*0.004m進(jìn)行諧響應(yīng)分析，在板的上部中心位置施加1000N的力，頻率范圍為530-540Hz。對(duì)此平板模型進(jìn)行模態(tài)分析，其結(jié)果如表1所示：表1平板模態(tài)分析二、有限元模型圖1平板模型圖2空氣介質(zhì)模型三、網(wǎng)格劃分圖3整個(gè)模型的網(wǎng)格劃分四、結(jié)果與分析圖4空氣介質(zhì)在平板振動(dòng)頻率為531Hz時(shí)的聲壓分布圖5空氣介質(zhì)在平板振動(dòng)頻率為534Hz時(shí)的聲壓分布圖6空氣介質(zhì)在平板振動(dòng)頻率為536Hz時(shí)的聲壓分布圖7空氣介質(zhì)在平板振動(dòng)頻率為538Hz時(shí)的聲壓分布圖8空氣介質(zhì)在平板振動(dòng)頻率為540Hz時(shí)的聲壓分布經(jīng)ANSYS求解，得到了表2所示的聲壓最大值和最小值，其內(nèi)部具體的分布情況如圖4至圖8所示。表2聲壓分布圖9聲壓最大值隨頻率的變化圖10聲壓最小值隨頻率的變化從圖9中可知，聲壓的最大值趨勢(shì)中的最大值出現(xiàn)在536Hz附近，與平板的一階模態(tài)536.03Hz相一致;同理，圖10中聲壓最小值分布趨勢(shì)中的最大值也出現(xiàn)在536Hz附近，可知，平板的振動(dòng)頻率達(dá)到它的固有頻率時(shí)振動(dòng)最大，從而使得其產(chǎn)生聲壓最大。程序清單---------------------------------/PREP7ET,1,SOLID45!殼單元類(lèi)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為鐵MP,EX,1,2.1E11MP,DENS,1,7800MP,NUXY,1,0.3!材料2為空氣介質(zhì)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!對(duì)編號(hào)為2的體劃分網(wǎng)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!對(duì)編號(hào)為4的體劃分網(wǎng)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!對(duì)編號(hào)為1的體劃分網(wǎng)格(此步驟劃分網(wǎng)格需要手動(dòng)進(jìn)行)VSEL,s,,,1VATT,2,,2!指定的材料屬性為空氣介質(zhì)(與結(jié)構(gòu)耦合)SMRT,1VMESH,1alls!修改不與平板(結(jié)構(gòu))接觸單元的材料類(lèi)型類(lèi)型為空氣介質(zhì)(不與結(jié)構(gòu)耦合)esel,s,type,,1nsle,sesln,s,0nsle,sesel,invensle,semodif,all,type,4alls!在邊界生成吸收單元。(使用單元fluid130)Asel,s,,,1,2NSLA,S,1type,3real,3mat,2esurf!Generateselementsoverlaidonthefreefacesofexistingselectedelements.alls!建立流-固接觸面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---------------------------------!第一種后處理方式，得到空氣介質(zhì)的聲壓分布，單位為分貝/soluantype,harmichropt,fullf,131,fY,1000.allsnsubst,10kbc,1HARF,337,337

!加載80Hz的頻率SOLVE!對(duì)與結(jié)構(gòu)耦合的空氣單元和未與結(jié)構(gòu)耦合的空氣單元進(jìn)行后處理，得到聲壓分布/post1SET,FIRSTesel,s,type,,2esel,a,type,,4PLESOL,NMISC,4,0,1.0---------------------------------!第二種分析后處理方式，!使用諧波分析法對(duì)530-540Hz頻率之間進(jìn)行頻率掃描計(jì)算第一階彎曲模態(tài)，從而檢測(cè)到結(jié)構(gòu)模型的固有頻率/soluantype,harmichropt,fullf,131,fY,1000.allsnsubst,10kbc,1HARF,530,540!加載頻率530-540SOLVE!檢測(cè)到結(jié)構(gòu)模型的固有頻率/post26plcplx,0nsol,2,1,u,x,d1uxstoreconjug,3,2prod,4,2,3sqrt,5,4*get,uxmx,vari,5,extrem,t