Virtual.lab聲固耦合的隔聲量仿真分析教程

1、FEM Direct Vibro-Acoustic An alysis Case TutorialObjective:The goal of this tutorial is to calculate the acoustic resp onse of a glass/PVB plate (a lam in ated safety glass with a Polyv inyl butyral layer in betwee n).The tutorial in cludes using the follow ing an alysis cases:Structural Modal caseD

2、irect Structural Forced Resp onseDirect Structural Vibro-Acoustic Resp onse*Tra nsmissi on LossThe model contains a Visco-elastic freque ncy-depe ndent material.Pre-Requisites:Software Configurations that are needed to run the tutorial:Lice nses to set up the case in LMS Virtual.Lab: "Desktop (

3、VL-HEV.21.1 or equivale nt)" and "Fi nite Eleme nt Acoustics (VL-VAM.36.2)"*Whe n solv ing the acoustic resp onse case, the lice nse for product "LMS Virtual.Lab FEM Vibro-Acoustics Structural Solver VL-VAM.45.2" is needed.Solvi ng the Ran dom Post-process ing case to get th

4、e Tran smissi on Loss curve will require the lice nse for "Ra ndom Vibro Acoustic An alysis (VL-NVP.20.3)"Tutorial Data Files:StructuralGroups.xmlSAFyou ng.xlsLam in atedStructure.bdfFPmesh.bdfAMLse nder.bdfAMLreceiver.bdfAcousticGroups.xml All data files can be found on the APPS n DOCS DV

5、D, in an archive called VAM_DirectVA-TL.For ease of use, it is best to copy all files to a local folder.STEP BY STEP Tutorial:STEP 1After start ing LMS Virtual 丄 ab Workbench ( Start -Acouslcreate a new docume nt in the Acoustic Harm onic FEM-Acoustic Harm on ic FEM).1#STEP 2#Select File -Import fro

6、m the main menu. The Import comma nd can also be selected from the con textual menu of the Links Man ager, by right click ingA file selector window appears allowing you to specify the file type and the file name. For more details, see Importing_Data_Select the file type NASTRAN Bulk File (*.bdf, *.N

7、S, *. nas, *.dat) and browse for the file Lam in atedStructure.bdfand click the Open butt on. A new dialog box appears request ingthe selection of data that needs to be imported from the file. The data entries that are not available in the file are grayed out.Select in Split into Multiple Mesh Parts

8、 under Mesh Creation and set the unit system toMeter,Kilogram, Second,click the OK butt on.STEP 3Next, the differe nt structural materials will be defi ned. The two outer layers of the panel are made of Glass . To in corporate the 2% structural damp ing of this material, it will be modeled asa visco

9、elastic material with a con sta nt complex You ng modulus. The inner layer is made ofPVB.In sert Materials -New Materials -New Viscoelastic Material.Right-click on the Materials feature in the Specification Tree T New Materials New Viscoelastic Material Define the materials as follows:GLASSPVBYou ng

10、 ModulusCon sta ntPoisson Ratio MassDen sityYou ngModulusPoiss onRatioMass De nsityRealImagi nary0.232500kg_m3Freque ncyDepe ndent0.491066 kg_m37.15e+011N_m21.401e+009N_m2Viscoelastic Material二-回鼻Voung Modulus:RealImajinaiy衿匚ondant|7J5e+011Nm211401009152 總| 0C1 Frequency DependentPoisson Ratio:RealI

11、mginary Constant| 0.23爭 | 0爭 & |O Freq uen cy D ep en d ertMa刖 Densily|Z500kg_m3g &|Apply CancelThe PVB material at the center of the windshield has strong frequency dependent stiffness properties and is n early in compressible. The freque ncy depe ndency can be in corporated in a viscoelast

12、ic material using an edited load fun cti on. The values can be imported from the Excel document SAFyoung.xls as follows:Check Freque ncy Depe ndent , and right-click the in put field.Select New Function3Vi sc oe I a stic Materi d= | IjF4#Name|PVB#RealImaginary* New Fun ction* oclrfy FunctionO Consta

13、nt10N_m2 耳 |QIM_m2 G |鼻 Frequency dependentRealPoison Rwtimfiemavt Fun匚tianA El毗怔 Furrctior Conitant'-1 Frequency DependentMass Density;|1066tg_m3§ 夕 |#In the Attributes tab , en ter as Name You ng ' s modulus PVBIn the Values tab, click the Import a file butt on, and browse to the exce

14、l file to select it.Lcbc Funcbcin Edi口itAttribuEes Values | Oyet-uew | MessagES | FIecorderVisible Stack! rl: q Qu O U O L-4 m I > IY IF-m2Jm INb- m2Phase r-,.|0|0K'WL isp Icy '/clus 陽 |Rjga；bljFTjginaiiyDe etsBasilJ用網(wǎng)ic | All Comfnand5 |Eiiitl/-r I+XSiFl2S- kJ廠Select Invert SElectizn |I

15、H12 UM ?聖CarKelSwitch the Data Format to Linear Amplitude/Phase (deg) because the file contains the values like that. Click the Import butt on.RowII區(qū)Import rrom XitfuheetAinpltudePVB Sfk Young Modulus Phase(fegiee<PVB SAF Yung Moddus PVB SAF Young Modulus 'At Linear3(160 )l .=E+07 32.61924307

16、k(200 )2.13E407 3Z.822D160B5(2S0 )2J3E+07 33.086755（呵2.51 E+07 33.623906157(100 )Z.eE-Ki?34-411143308()3.FSE-I-O7 j35_18383»6629(630 )4.06E4O?36.1294+4 HID(sw)5,.E3E-O7 37.052S045411(1U0U )b.ttJE+07 j:38.3lte/3bb/Click the OK button of the Function Editor GUI.Click the OK button on the Material

17、 GUI.On the Edited Load Fun ction Set, create (usi ng the con text me nu) a 2D display of typeComplex (Edited Load Fun cti on) on the You ng' s modulus and check the curve:JJSi+nctiSA+OQflL73«tQItSfl+M1»+CKflla iQOfl9 430TVl.49ye 亠 UDB5#4510?' ' 1ffnot f is-Furcfidni Clisd-1円!f

18、aJ T祁聲| toLJiOSitlDbail C<itu flPIII 1 Odar'MurrtMfJU-s-皿旳nvMIAii! PvflvOuhQ UQDULlIli:1QKiMlIII F4O951 I#STEP 4Defining two Structural 3D properties for Glass and PVB, applied to the structural groups Glass (with the defi ned material Glass) and PVB (with the defi ned material PVB).In sert-P

19、roperties-New Structural Properties -Create 3D-PropertyRight-click on the Properties feature in the Specification TreeNew Structural Properties-Create 3D-PropertyPipcrty Definition卩陽Application Rfgian:e瀕r.lare Pararieen J 匚 Advanced PaameCer LcrngFeatu rccguircsBefore the following steps please make

20、 sure the Mesh Parts are defined as types:PROPERTY0 - StructuralGlass - StructuralPVB - StructuralThis can be done by going to Tools Tset Mesh Parts TypeRight-click on the mesh in the Specification Tree,Set Mesh Part TypeSet as StructuralMesh PartSTEP 5In the n ext step, the model mesh will be impor

21、ted from two Nastra n in put files. They each con ta in a mesh on which we will apply an AML property (Automatically Matched Layer), one on the receiver side, and one on the sen der side.:File -Import Acoustic MeshUse Meter, Kilogram and SecondsModel Mesh. , and select the file AMLreceiver.bdfun its

22、, and in clude the materials and properties.At this point the mesh parts type definition window should look like this:blameTypePROPERTY 0StructuralGias?StructurdPVBStructuralAMLreceverAcousticalAcoustic EnyelQpe.lAcousticalAMLsenderAcousticalParB TypeSet as AcousticalSet as Field PointStatusDeactiva

23、te Show Oeactr/atecl Mesh PartsType軋t少弘ut辿對STEP 6In sert ing theNew Material and properties for the new imported meshesInsert a new Acoustic material as follows (use the default values for air):Similarly, import AMLse nder.bdf7Fluid Material340m sCm 5Rpply J fari 匚呂 I0 Frequency DependentMass Densit

24、y:RalImaginary CcrstantL22Skg_m3囹|呃m(xù)囹3O Frequency DependentParameters 8#In sert also aNew Fluid Property . Call it also air, use the just defi ned material 'Air', and applyit to the two Acoustic mesh parts (Sender and Receiver side).Acoustic Fluid Property a Erame New Acoustic Fluid Pmperty.

25、lApplication Reg ion:12 Mesh PartsEdit |Pfcpetty ID：ShCUJ卩站311毬占£ #CancelSTEP 7To facilitate the creati on of the structural and acoustic model, some eleme nt groups have bee n predefined in xml files. To import these groups, first create mesh group sets.In sert a New Group Set , either from th

26、e con textual menu or withInsert Mesh Group ingGroup Set.By right clicking the Group Set feature in the Specification Tree, insert a mesh group namedStructural Groups, and in it import the 5 groups from the fileStructuralGroups.xml.Group Selectio n DialogRight-click the Group Set, and useMesh Group

27、ingSimilarly insert a mesh group namedAcoustic Groups, and in it import the 4 groups from the fileAcousticGroups.xmlRight-click the group set, and use againMesh GroupingGroup Selection Dialog:Step 8Save the analysis, but without closing.SETTING UP THE ACOUSTIC CASESStep 1In sert a new acoustic autom

28、atically matched layer property to take into accou nt the semi-infinite extent of the sender and receiver rooms. Insert a new AML property by right-clickingProperties, use New Acoustic PropertiesAutomatically Matched LayerProperty.Apply it to the two Acoustic groups AML Receiver and AML Sen der. Swi

29、tch the Radiation surface to User Defined , and select the AML Receiver group .AutomaticaKy Mate hed la yer PropertyName | Autamaticlly hatched Layer Propertyr 1Applicatioc ReonXRadiatton surFace for Far-fieldl calculation luser DefinedRmEation wirfateShow More Pflrdmaerg . jII 速 III Appt匚 ancel2 Gr

30、oups10#Step 2Insert a Direct Vibro-Acoustic Response Analysis Caseto compute the structural responseand acoustic pressure fields in both the sender and receiver acoustic domains for each of the distributed pla ne wave excitati ons:To perform this calculation use No Load function Set and No Load Vect

31、or Set .Create new sets for all the rest.STEP 3Expa nd the Direct Vibro-Acoustic Resp onse An alysis Casefrom the Specificati on Tree,right-click theBoundary Condition Setand use Acoustic SourcesDistributed PlaneWaves. with a Refinement Level of 2, a Radius of 4m, and an Acoustic Pressure on 1Pa . T

32、he plane waves will be used to excite the system and to calculate the transmission loss characteristics of the pan el.Since the panel is not alig ned with the xy pla ne, this coord in ate pla ne cannot be used to defi ne the locati on of the pla ne wave sources. So, for theHalf Space Pla ne select P

33、lane defi ned byGroup and select the acoustic groupCoupli ng Sen der .Select the Negative Half Space side.Click the OK butt on to gen erate a set of 12 spatially distributed pla ne waves.By now the model should look similar to this:sj-ini 軒Drel “弟屆gjJii nrile -frt 丹 iMStep 4We will now restra in the

34、 border of the glass pan el.Right-click the Restraint Set , add an Advaneed Restraint on the 3 Translational DOFs, and use as support the Structural Group BCs .Step 5Coupling surface definition will be used to couple the upper and lower surfaces of the panel to the en velope surface of the acoustic

35、cavity. When sett ing the Coupli ng Surface, the coupli ng betwee n the structure and the fluid is on both sides.To correctly define the two-sided coupling in a transmission loss calculation, two couplingsurfaces n eed to be created. From theCoupli ng Surface Set.1 feature, double-click theCoupli ng

36、 Surface Set.1 , and add the two surfaces:Structural Group Coupli ngSe nder andAcoustic Group Coupling Sender . Use a toleranee of 10mm and select as Coupling Type One side. Click the Apply butt on.GlriSSCoupi ngS 電Cotjpl rig SenderAcoustic GroupsRestrairt SetEdited Load Function SellAcoustic Mesh P

37、reprocessing Set.1匚 cup ingRece vyrir電ct匸匚尺色gpcnER An自lysH 亡目鳥。CouDlincrj Acoustic Bondary Conditions and ScurcesStructural Groups1 AML 矗mb" AMLCoupling ReceiverCoup hg SLrtce Sell jCouDlinq Surfice.li卜Create Coupling SuiTolerjrKe10mmCoupling Surface !CnupNng Type* One Side O Both SidesApply fa

38、rKEName Coupling SvrfaceAStructural GroupsyMesh PartsCoLplingSenderAcoustic Groups/Mesh PartsDo the same for the Receiver Side in the end you should have two Coupling surfaces:Step 6Double-click on the Direct Vibro-Acoustic Resp onse soluti on to update the an alysis parameters.In the curre nt tutor

39、ial, the resp onse at the cen ter freque ncies of the third octave bandsbetween 160Hz and 2000Hz will be analyzed. In the Result Specifications tab, select User Defined values for the Argume nt Axis Defin iti on and remove the sta ndard an alysis freque ncy range. Add a new frequency range definitio

40、n and select aLogarithmic Step definition with astarti ng freque ncy of 160Hz , an en di ng freque ncy of2000Hz and a step of 1.122462048Click the OK butt on to add the freque ncy range defi niti on.Request Vector results at Field Points and for the Acoustic Potentials.No need to solve forStructural

41、 Displaceme ntsfor now.Adjust the Solv ing Parameters . If your system is set up for parallel process ing (see theAdvaneed Acoustic Installation manual), try one of the Parallelism types. Use the Direct solver.Adjust also the Job and Resources, e.g. to use multiple threads.Leave the Output Sets empt

42、y, meaning that results will be computed wherever possible.Edit Solution ParaniotorsRflsUt peaficabtns ；|Promotal | JobmdRssmitnsArgiment An Q eri Hun Pramec ersO U?e Axis orf F盤 Function of FSt vgdHori User Defined ¥du«Loq3ri&iint5tSiStaFt - 160, End-2000,環(huán)-1.12246Ma jimurn "Valu

43、e: bniR theWanfleNnlmun Value:庚E 訃削 F»cld Pp<ni-<O Sdv«ftdd. I iteflSB _! Rmww編 _ Mt,“ f incort“* I uat 滋11)>5“* 1 Saw »MtnnQ Sae 逍 FirKticju3QK C4nc«l15#Step 7Update the Direct Vibro-Acoustic Resp onse Soluti onto compute the acoustic pressurefields and structural defor

44、mations. This will take a while, as there are23 frequencies and12load conditions.Save your model.Step 8Display ing the resultsOnce the computation is finished, right-click theDirect Vibro-Acoustic Response Solution Set.1feature and selectGen erate Image from the con textual menu.or select the soluti

45、 on feature and click theGen erate Imagetoolbar butt on.The Image Gen erati on dialog box will appear, select thePressure.Double-click the image feature in the Specificati on Tree, and in theOccurre nces tab selectthe for example the first Load Condition (meaning the loading by the first distributed

46、 plane wave source) and set the freque ncy at508Hz , click the OK butt on. For better visualizati on youcan hide the Nodes and Elements feature, and the Boundary Conditions feature (with its plane wave sources).Im-age EditionI| r1Visu Selections ; Occurrences"in imnmie“ei“u iiDfita CdseLoad Con

47、dition #1 oflZLoad 匚 ordtion #2 of21ZLoad CorAiori #3 qF 12Load 匚ordtiori #4 oM2Load Condition 45 of 12Load Condition #6cf 12Load Cjondtion 47 of 12Load Cocdition #Sof 12Load Cordtion #9 of 12Load Condtiori #10 of 12Load 匚 ordfcian #11 of 12Load CjondUon #lZof 1Z160Hz179.594Hz201,507Hz226,273Hz253.9

48、B2HZ285,035Hz 319.»6Hz 359.1S3H2 403,169Hz 452,541Hz1507,959Hz570.164Hz 639,?S6Hz 716,359Hz 606.329Hzv|Frequency16#ricireAA OK Canal Pfev旦；(AFressue 丁口曲 vaMes).Ocojnencje 11M_m20.4620.36E03140.160.0918-0.13-0.270Cn Bocnd 也Image MacneFruueqcyRi唱;m© inodiv.litas'' 1load COrtdilKTl #1

49、 d 12You can also display the 2D image curvefor the Acoustic Power on the Kirchhoff surfaceRight-click the Direct Vibro-Acoustic Resp onse Soluti on Set.1feature and select NewFun cti on Display. . from the con textual menu. The New Fun cti on Display dialog box will appear requesti ng you to select

50、 the differe nt display images.Also you can use the butt on from the toolbar and select the Soluti on Set feature. A third possibility is to use the menu Insert T2D/3D ImagesNew Fun cti on Display Select the 2D Display from the list and click the Fin ish butt on.A new win dow, containing X- and Y-ax

51、es along with theSelect Data dialog box will now appear.In the Select Data dialog box, select Kirchhoff Surface Radiatio n: S and click the Display butt onAs each of the distributed pla ne wave sources are in depe ndent, the sou nd power can beobta ined by simply addi ng the in dividual con tributi

52、ons. So, select all12 Data Cases, andcheck the opti onSum over data cases .Switch the x-axis format toOctaves, and the Y-axis to dB(RMS). You can use dot markers forthe curve by right-click ing it, using the Opti on s. comma nd in its con text menu, and the n cha nging the sett ings in the Visualiza

53、ti on tab.17HE恤 m|Cw| W* |*lb<- j日moiiK Aacow &31mm l253 90218#Save your modelStep 9To get the transmission loss curve, we need to divide the total acoustic power on the receiver side by the total power on the sen der side. Before we can do that, we n eed to comb ine the in dividual cases (on

54、e for each distributed pla ne wave source) to get the total power curves.Insert a Random Post-processing Case with Insert TOther Analysis CasesRandomPost-Process ing Case.Refer to the soluti on of the previous response case, and select to process for aCross Power Setwith Uni tary Un correlated Load

55、Cases:Update its soluti on using the con text menu on its soluti on featureRan dom Resp onseSolution Set.X. This will go fast.Right-click the sub-solutionGlobal Indicator Set.X and create a New Function Display on it.Select the 2D Display as sce nario, and click the Finish butt on.A 2D display win dow will appear with theSelect Data dialog box ope n. In theGen eral tab,switch the drop-down selector toTransmission Loss , and select the entry Coupled Surface:Sand click