平板的ANSYS聲學(xué)分析

1、平板的聲學(xué)分析Lordtomorrow一、 參數(shù)說明板的總體尺寸為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530540Hz。對此平板模型進(jìn)行模態(tài)分析，其結(jié)果如表1所示：表1 平板模態(tài)分析階數(shù)頻率（Hz）1536.032658.0931447.441487.952195.2二、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)在平板振動頻率為531Hz時的聲壓分布圖5 空氣介質(zhì)在平板振動頻率為534Hz時的聲壓分布圖6 空

2、氣介質(zhì)在平板振動頻率為536Hz時的聲壓分布圖7 空氣介質(zhì)在平板振動頻率為538Hz時的聲壓分布圖8 空氣介質(zhì)在平板振動頻率為540Hz時的聲壓分布經(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 聲壓分布頻率（Hz）聲壓最大值（dB）聲壓最小值（dB）531168.84866.019532171.08268.143533174.01170.998534178.32875.278535186.93283.884536190.6287.611537179.81276.877538175.22472.398539172.29569.608540170

3、.15167.632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中的最大值也出現(xiàn)在536Hz附近，可知，平板的振動頻率達(dá)到它的固有頻率時振動最大，從而使得其產(chǎn)生聲壓最大。程序清單-/PREP7ET,1,SOLID45 !殼單元 類型1ET,2,FLUID30 ! acoustic fluid element with ux & uy(0-Structure present at interface (unsymmetric element

4、matrix)ET,3,130 ! acoustic infinite line elementr,3,0.3,0,0ET,4,FLUID30,1,0 ! acoustic fluid element without ux & uy(1-No structure at the interface (symmetric element matrix)! material properties!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,

5、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 !Overlaps volumesVOVLAP,3,4 !對編號為2的體劃分網(wǎng)格lesize,9,20,1lesize,19,20,1lesize,14,20,1lesize,18,20,1lesize,11,20,1lesi

6、ze,16,20,1lesize,12,20,1lesize,17,20,1lesize,8,4,1lesize,15,4,1lesize,13,4,1lesize,10,4,1VSEL,s,2VATT,1,1 mshkey,1 !Specifies whether free meshing or mapped meshing should be used to mesh a model.1 Use mapped meshing.VMESH,2alls !對編號為4的體劃分網(wǎng)格lesize,32,20,1lesize,31,20,1lesize,35,20,1lesize,33,20,1les

7、ize,28,20,1lesize,34,20,1lesize,20,4,1lesize,27,4,1VSEL,s,4VATT,1,1 mshkey,1 !Specifies whether free meshing or mapped meshing should be used to mesh a model.1 Use mapped meshing.VMESH,4alls !對編號為1的體劃分網(wǎng)格(此步驟劃分網(wǎng)格需要手動進(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)）接觸單元的材料類型類型為空氣介質(zhì)（

8、不與結(jié)構(gòu)耦合）esel,s,type,1 nsle,s esln,s,0 nsle,s esel,inve nsle,s emodif,all,type,4 alls!在邊界生成吸收單元。（使用單元fluid130）Asel,s,1,2NSLA,S,1type,3 real,3 mat,2 esurf !Generates elements overlaid on the free faces of existing selected elements.alls !建立流固接觸面Asel,s,8Asel,A,10Asel,A,7Asel,A,5Asel,A,19Asel,A,15Asel,A,

9、17Asel,A,20NSLA,S,1esel,s,type,2sf,all,fsi,1 alls-!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/solu antype,harmic hropt,full f,131,fY,1000.alls nsubst,10kbc,1HARF,337,337 !加載80Hz的頻率SOLVE !對與結(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/post1 SET,FIRST esel,s,type,2 esel,a,type,4 PLESOL, NMISC,4, 0,1.0 -!第二種分析后處理方式，!使用諧波分析法對530540Hz頻率之間進(jìn)行頻率掃描計算第一階彎曲模態(tài)，從而檢測到結(jié)構(gòu)模型的固有頻率/solu antype,harmic hropt,full f,131,fY,1000.alls nsubst,10kbc,1HARF,530,540 !加載頻率530540SOLVE !檢測到結(jié)構(gòu)模型的固有頻率/post26plcplx,0nsol,2,1,u,x,d1uxstoreconjug,