The Modeling of Unconventional Sound Absorbing Materials: Microperforated Films and Closed Cell Foams

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1 Purue Universiy Purue e-pubs Publicaions of he Ray W. Herric Laboraories School of Mechanical Engineering The Moeling of Unconvenional Soun Absorbing Maerials: Microperforae Films an Close Cell Foams J Suar Bolon Purue Universiy, bolon@purue.eu Follow his an aiional wors a: hp://ocs.lib.purue.eu/herric Bolon, J Suar, "The Moeling of Unconvenional Soun Absorbing Maerials: Microperforae Films an Close Cell Foams" (03). Publicaions of he Ray W. Herric Laboraories. Paper 0. hp://ocs.lib.purue.eu/herric/0 This ocumen has been mae available hrough Purue e-pubs, a service of he Purue Universiy Libraries. Please conac epubs@purue.eu for aiional informaion.

2 J. Suar Bolon Ray W. Herric Laboraories School of Mechanical Engineering Purue Universiy Sociéé es Ingénieurs e l'auomobile Conférence: Lighweighing an Acousical Maerials in Vehicles. UTC, Ocober, 03

3 Recenly, i has been observe ha o Macro-cellular polyolefin foams (e.g.,quash-lie) absorb soun energy even hough he foams are mosly closecelle an he average cell size is very large. How oes his soun absorpion arise? How o you moel his effec?

4 - Moel is base on ensione membranes - Siffness of his moel is provie by ension of membrane Sress Top View of Quash Membrane Tension 3

5 3-D Moel -D Moel Soun Energy Loss Mechanisms Energy issipaion by membrane fleure Viscous loss hrough perforaion Uni cell Membrane Thermo-viscous bounary layer effec Rigi Frame Maerial Properies Tension Loss facor Membrane Densiy Surface Film Densiy Porosiy Flow Resisance 4

6 I INCIDENT WAVE FLUID II REFLECTED WAVE TRANSMITTED WAVE TENSIONED, PERMEABLE MEMBRANE o Soun Pressures in Acousic Caviies: Assume Soluions 0 erm=r 0 erm=t o o Membrane Displacemen (Soli Componen): Membrane Displacemen (Flui Componen): 5

7 = o Bounary Coniions - The Coninuiies of Velociy a he Boh Sie of a Membrane: j j o o PI z P z II z z 0 0 ( ( ) ) y y u u o Soluion Meho Apply four bounary coniions on a poin-by-poin basis across he membrane I Paricle Posiion II r - The Force Equilibrium Equaion in he Membrane: T y o T s h T o ( j y u ) R T f R f ( y ( y u) N a / u) A ( T P ( P fron ) ( P I P bac I P II ) P R II f ) v f ~ Number of Poin a which B.C. s applie y Coefficien Mari A... A B... B C... C N 0 N 0 N Forcing Vecor 6

8 o Given eperimenal resuls as inpu, Fin appropriae maerial properies (T o, ρ s, η ) TL I II Membrane Surface Densiy ρ s Membrane Tension T=T o (+i ) Tensione Membrane T 8Pa s g m Noe : Mos absorpion resuls from ransmission hrough membrane in anechoic erminaion case 7

9 Membrane & Air Caviy Transfer Mari T m = 0 Z m T a = cos( ( l l)) i oc sin( ( l l)) i ocsin( ( l l)) cos( ( l l)) Toal Transfer Mari N layers P u Top Top = T oal P u Boom Boom Toal = Tm s Ta Tm Ta Tm Ta Reflecion Coefficien R Top Z Z Top Top o o c c o o layer layer Absorpion Coefficien RTop N layers 8

10 B&K Pulse Sysem Power Amplifier Signal Analyzer Pre-Amplifier Compuer Soun Source Microphone Saning Wave Tube Quash Sample 9

11 Noe relaively large absorpion in zero porosiy case m= g/m, T o =0.3 N/m, =.6, m s =0.586 g/m, Ω=0.0085, R f =0.86 Rayls, =0.000 m, o = m, h= m, N=. 0

12 New Design m=0.3 g/m ( ), T o =0.065 N/m ( ), =.6, m s =0.94 g/m ( ), Ω=0.0( ), R f =0.86 Rayls, =0.000 m, o = m( ), h= m, N=0( ) New Design m=0.770 g/m ( ), T o =0.3 N/m, =.6, m s = g/m ( ), Ω=0.03( ), R f =0.86 Rayls, =0.000 m, o = m( ), h= m, N=0 ( )

13 An acousical moel for membrane-base soun absorbing maerials was presene an was verifie eperimenally on he basis of acousical measuremens. Major issipaion mechanism is he fleure of membrane no visco hermal (unlie convenional fibrous meia). The presen wor can provie he founaion necessary o esign membrane-base soun absorbing maerials having enhance soun absorpion capaciy. The presen wor implies ha alernaive siffness mechanisms of membrane sysems such as fleural siffness, membrane curvaure, bul elasiciy, as well as membrane inhomogeneiy, can conribue o soun issipaion in membrane-base foams.

14 Ligh weigh polymer films 3

15 Perforae Films Maerial Parameers Air space Viscous Dissipaion l Surface porosiy (%) Hole size (0. mm) Bacing space eph Hole eph (0.3 mm) Complicaing facors o Fleibiliy of he film o Non-cylinrical hole shapes Owing o low acousic mass an relaively large viscous losses, absorpion banwih can be relaively large. α 4

16 z Z 0 c r Perforaion consan Resisance r 3( c j m 0 ) Conribuion from hole Z : specific acousic impeance of single hole σ: porosiy r: resisance m: effecive mass per uni area f 3 Relae o bounary layer 8 : hole iameer f: frequency : hole eph c: spee of soun μ: inemaic viscosiy ν: hermal conuciviy L: bacing eph En correcions (effec from flow over ouer surface an convergence ino an ou of holes) Reacance Absorpion Coefficien m c 9 n ( r) 4r m co L c Panel is assume RIGID in Maa moels: no fleural moion is consiere 5

17 Subsanial change in Resisance No much change in Reacance Moels Perforaion consan Resisance Reacance 975 High hermal conuciviy moel- Scienia Sinica 0 f r 3( c ) 3 8 m c 975 Low hermal conuciviy moel- Scienia Sinica 36 f r 3 c 3 8 m c Noise Conrol Engineering Journal 4 0 r 3 c m c Journal of Acousical Sociey of America 4 0 r 3 c 3 3 m c : hole iameer, f: frequency, : hole eph, c: spee of soun, μ: inemaic viscosiy, ν: hermal conuciviy, η: viscosiy coefficien (=μρ 0 ) 6

18 FE coe Comsol was use primarily o Incompressible, isohermal, D aisymmeric o Inle: Hann-winowe, 5 Hz half-sine (0. ms) - velociy o Run 0.5 ms for accurae saic flow resisance o Maimum spee of mm/s o Represens infinie square array Cylinrical cener line 7

19 Typical Resuls Reversible, laminar flow hrough hole (Re ) o No non-linear effecs since we have low velociy Seconary moions in ime-epenen cases 8

20 A pilo suy on improving he absorpiviy of a hic microperforae panel absorber, Saagami e al. Wih of a uc Three apere holes 9

21 # # #3 #4 #5 #6 #7 #8 0

22 Tapere Holes wihou En Correcions L r r r r A r r j J j J j j L / / / Z 0 0 Taper Easily calculae numerically using coes such as Ocave, MaLab, or Mahemaica ovalue compue a each frequency poin

23 Tapere Hole En Correcions Z * L 3 r r r r L 3 r r r r r 3 r 3 Z Taper Thomas Herle

24 Sample number Hole iameer [mm] Hole eph [mm] Number of holes per m / Mass/area [g/m ] Porosiy [%] Sample (00) Sample 3 (00) Sample 0 (00) 3

25 Sample Sample 3 Sample 4 Wih of a uc Air bacing ephs are 0 mm an 0 mm 4

26 Fleible panel case P I Volume velociy coninuiy a =0 j j o o pi p II 0 0 ( ) ( ) s Force equilibrium a =0 Soli Flui p p I I p p II II s f f ( f s) 4 R D s T s s R ( f s ) j o h' f s P II z y p I : Pressure a source sie p II : Pressure behin he panel s : Displacemen of soli par f : Displacemen of flui par ρ s: Membrane mass per uni area R f : Flow resisance D: Fleural siffness T: Tension h : Effecive hicness Ω: Porosiy 5

27 3-imensional moel P I L z z L y P II y Only symmeric moes eis P I P II e j m 0 n 0 m 0 n 0 m Soun pressure in each region C mn B mn cos( cos( m m n n L L z y (m, n=0,,, ) Displacemen of membrane m z)cos( z)cos( n y) e j n j y) e mn m m j mn mn n n e j mn ( L) (> n + m ) (< n + m ) for simply suppore BC Soli par s m n A mn sin m z sin n y for clampe BC Soli par s m 0 n 0 A mn cos m z cos n y Flui par f m 0 n 0 F mn cos m z cos n y Flui par f m 0 n 0 F mn cos m z cos n y m m L z, n n L y (m, n=,, ) 6

28 Sample (00) Sample (50) Sample 3 (50) (nominal) [mm] [mm] ρ s [g/m ] Sample Sample Sample N 7

29 n n n S (nominal) [mm] (ajuse) [mm] [mm] D / loss facor [N m ] T [N] ρ s [g/m ] N S / preicion B.D.= cm measuremen B.D.= cm 0. preicion B.D.= cm measuremen B.D.= cm 0. preicion B.D.=4 cm measuremen B.D.=4 cm Freq [Hz] 0.9 S S S S3 0.7/ / preicion B.D.= cm measuremen B.D.= cm 0. preicion B.D.= cm measuremen B.D.= cm 0. preicion B.D.=4 cm measuremen B.D.=4 cm Freq [Hz] preicion B.D.= cm measuremen B.D.= cm 0. preicion B.D.= cm measuremen B.D.= cm 0. preicion B.D.=4 cm measuremen B.D.=4 cm Freq [Hz] 8

30 n [mm] [mm] D [N m ], 0.6, 0.4, 0.3, 0., 0., 0.0, loss facor in D T [N] Mass/area [g/m ] N Size [mm] Depening on he fleural siffness, he absorpion performance can be enhance wih a proper loss facor D0= D0= D0=0.4 D0= D0=0. D0=0. 0. D0=0.0 D0= Freq [Hz] 9

31 Lengh of a uc DUCT Wih of a uc Deph of a caviy o Microperforae Surface Normal Impeance y Lengh of a caviy o Fibrous Surface Normal Impeance 30

32 Transmission loss of uc linings Local reacion reamen (Analyical approach) Local reacion reamen (Finie elemen approach) 3

33 Applicaion of Micro-Perforae Composie Acousic Maerial o a Vehicle Dash Ma Alan Parre, Chong Wang, Davi Nielubowicz, Xiani Zeng, Mar Snowen, General Moors Jonahon Aleaner, Ronal Geres 3M Corporaion Bill Leeer, Charles Zupan Janesville Acousics

Micro Perforae Film Consrucion Micro-Perforae polymer film on

absorpion In orer o enhance performance, an EVA barrier layer

34 Micro Perforae Film Consrucion Micro-Perforae polymer film on fibrous ecoupler Concep places mass layer a he surface o maimize STL. Perforaion size an ensiy of holes has srong effec on STL an absorpion In orer o enhance performance, an EVA barrier layer wih larger holes was applie o simulae ae mass in he film (ooling for hicer film was no available a he ime) SAE

35 Large SUV Resuls Summary (Ariculaion Ine (AI), Overall Average (OA) B an Louness (Sones) Dashma (g) Baseline (6.5) Base MrPF (.8) s Gear, 4000 erpm 6-35 ph WOT Acceleraion (AVG) OA BA AI % Louness (Sones) OA BA Enhance MrPF (6.6) g/m Barrier (0) Noe: Re=Improvemens over he baseline ashma, SAE

36 Pracical Applicaions Poenial applicaions in car inerior esign Healiner A pillar + hoo liner, inucion sysems, HVAC sysems Carpe 35

37 The performance of lighweigh maerials can be accuraely preice using a combinaion of analyical an numerical ools (incluing FEA moels) There are many poenial lighweigh auomoive applicaions in inerior sysems an oher areas of he vehicle SAE

38 Nicholas Kim an Seung-yu Lee (Purue) Former suens Jinho Song (Ois Elevaors), Taewoo Yoo (3M Corporaion) an Kang Hou (GoerTe Inc.) Colleagues Chung Par, formerly of Dow Chemical, Jonahan Aleaner, Thomas Herle, Thomas Hanschen an Ron Geres from 3M Corporaion, an from General Moors Corporaion, Alan Parre Financial suppor from Dow Chemical an 3M

J. Song an J.S. Bolon, Soun absorpion characerisics of membrane-base soun absorbers, Proceeings of INTER-NOISE 03, 388-3888 (003). J. Song an J.S Bolon, Acousical moeling of ensione, permeable membranes, Proceeings of NOISE-CON 003, 965-970 (003).

39 J. Song an J.S. Bolon, Soun absorpion characerisics of membrane-base soun absorbers, Proceeings of INTER-NOISE 03, (003). J. Song an J.S Bolon, Acousical moeling of ensione, permeable membranes, Proceeings of NOISE-CON 003, (003). T. Herle, J.S. Bolon, N.N. Kim, J.H. Aleaner an R.W. Geres, Transfer impeance of microperforae maerials wih apere holes, Journal of he Acousical Sociey of America, 34(6) P., pages (03). Taewoo Yoo, J. Suar Bolon, Jonahan H. Aleaner an Davi F. Slama, An improve moel for micro-perforae absorbers, Proceeings of NOISE-CON 007, , Reno, Nevaa, Ocober 007. Taewoo Yoo, J. Suar Bolon, Jonahan H. Aleaner an Davi F. Slama, Absorpion of finie-size micro-perforae panels wih finie fleural siffness a normal incience, Proceeings of NOISE- CON 008, Dearborn, Michigan, July 8-3 (008). H. Shin an J. Suar Bolon, Microperforae maerials as uc liners: Local reacion versus eene reacion, Proceeings of NOISE-CON 0, (0). A. Parre, C. Wang, X. Zeng, D. Nielubowicz, M. Snowen, J.H. Aleaner, R.W. Geres, B. Leeer an C. Zupan, "Applicaion of micro-perforae composie acousic maerial o a vehicle ash ma," SAE Technical Paper , 0, oi:0.47/ (0). K. Hou an J.S. Bolon, Finie elemen moels for micro-perforae maerials, Proceeings of INTER-NOISE 009, (009).

Validation of Micro-Perforated Panels Models

Validation of Micro-Perforated Panels Models Purue Universiy Purue e-pubs Publicaions of he Ray W. Herrick Laboraories School of Mechanical Engineering 10-008 Valiaion of Micro-Perforae Panels Moels J Suar Bolon Purue Universiy, bolon@purue.eu Kang