Noise from structure borne sound sources mounted on lightweight receivers; progress report from CEN/TC126/WG7

Transcription

1 Nose from structure borne sound sources mounted on lghtweght recevers; progress report from CENTC126WG7 Mchel Vllot CSTB (Center for Buldng Scence and Technology), France COST FP0702 workshop, Delft COST FP0702 workshop, Delft, November 2010 PAGE 1

2 Servce equpment nose: standards avalable Goals and standards avalable: - Nose n buldng calculated from source power: - method avalable n EN : Source power measured n laboratory: - method avalable n EN :2009 Sructural source ns,j Recevng room Example of structure borne transmsson Euronose 09, Ednburgh, Cost FP0702 October workshop, 2009 Delft, November 2010 PAGE 2

3 Arborne sound source (1) Sound level n source room: - Normalzed sound level (reverberant feld) readly obtaned from source power level: na Wa 4 ( usually, no nformaton on source drect feld and source drectvty) (A s ) S na,j j Recevng room Sound level n adjacent room: - Normalzed sound level na,j (reverberant feld) calculated for each path j from source power: na,j Wa D s 10lg( S S ref ) R j,ref 10lg( Arborne transmsson: sound level n recevng room A ref 4 ) Incdent dffuse ntensty Flankng sound reducton ndex accordng to EN Transmsson term D s 10lg( S A s ) Euronose 09, Ednburgh, Cost FP0702 October workshop, 2009 Delft, November 2010 PAGE 3

4 Arborne sound source (2) Remarks lmtatons: - f the source s enclosed, ts sound power s attenuated by the sound power nsulaton D W of the enclosure: Wa,source - common case of arborne sound source close to a wall floor: ncdent power no longer dffuse 1 (domnant grazng ncdence and or localzed arborne exctaton smlar to mechancal exctaton); more work needed Wa D W [1] M.Vllot, C.Gugou, Arborne sound nsulaton: case of a small arborne sound source close to a wall, ICA Kyoto Japan 2004, proceedngs Euronose 09, Ednburgh, Cost FP0702 October workshop, 2009 Delft, November 2010 PAGE 4

5 Structure borne sound source (1) Sound level n adjacent room: - Normalzed sound level ns,j (reverberant feld) calculated for each path j: ns,j Ws,nst, D sa, R j,ref (1) (2) (3) 10lg( S S ref ) 10lg( A ref 4 ) Calculaton n 3 steps: (1) nstalled power (structural power njected): work of CENTC126WG7 (2) adjustment term to estmate the ncdent arborne power generatng the same vbratonal energy n recever D sa, R 10lg 10lg( 2f m c ) 10lg S ns,j j Recevng room (3) use of EN (arborne sound nsulaton) Structure borne transmsson: sound level n recevng room Euronose 09, Ednburgh, Cost FP0702 October workshop, 2009 Delft, November 2010 PAGE 5

6 Structure borne sound source (2) Case of tmber based lghtweght buldng: - adjustment term (on-gong actvty at CSTB): D sa, R * 10lg 10lg( 2f m c ) 10lg s - resonant transmsson only R*, σ s - m and η from dffuse feld power balance: valdty? W nj.2f.m. v 2 - nstalled power (on-gong actvtes n CENTC126WG7) - remark: - nstalled power: laboratory data n frequency range down to 50 Hz - laboratory data used n EN known wthn frequency range Hz Euronose 09, Ednburgh, Cost FP0702 October workshop, 2009 Delft, November 2010 PAGE 6

7 Installed power estmaton (from CENTC126WG7): Estmaton of the nstalled power (CENTC126WG7)(1) - Defntons: - free velocty: velocty at contact ponts of source dsconnected - moblty: rato velocty force appled - Installed power depends on both source (free velocty and moblty) and recever (moblty) Case of heavy (concrete) structures - Installed power estmated n EN n the smple case where recever moblty s much lower than source moblty; case of most buldng equpment mounted on concrete structures v EN laboratory setup (stage 1) - source mounted on a recepton plate n laboratory (so-called stage 1); power estmated from recepton plate velocty level measurements then lab to feld correcton : 10lg(Y, buldng Y, recepton ) Euronose 09, Ednburgh, Cost FP0702 October workshop, 2009 Delft, November 2010 PAGE 7

8 Estmaton of the nstalled power (CENTC126WG7)(2) Case of tmber based lghtweght recever (1): - source moblty mght be of the same order as recever moblty need to estmate the source moblty - determnaton of the source moblty: - rough estmaton usng examples and gudelnes - calculated from smplfed model of the source (mass, sprng ) - drect measurement wth reference to relevant standards - two stage method (B. Gbbs) Examples of mobltes (from B.Gbbs & A.Moorhouse) Euronose 09, Ednburgh, Cost FP0702 October workshop, 2009 Delft, November 2010 PAGE 8

9 Estmaton of the nstalled power (CENTC126WG7)(3) Case of tmber based lghtweght recever (2): - determnaton of the nstalled power: - f buldng element moblty much lower than source moblty: the whole method used n EN can be used - f buldng element and source mobltes of the same order, a smplfed mrror condton expresson of the power can be used : P nstalled N N Effectve recever moblty at contact pont (can be estmated 2 ) Y Y j F F j Y, j Re(1 Y R, Euronose 09, Ednburgh, Cost FP0702 October workshop, 2009 Delft, November 2010 PAGE 9 ). N v Sf 2 Source free velocty at contact pont [2] A. Mayr, B. Gbbs, On the use of sngle equvalent exctaton to estmate the structural power from machnes on tmber jost floors, ICSV Krakow Poland 2009, proceedngs

10 Estmaton of the nstalled power (CENTC126WG7)(4) Case of tmber based lghtweght recever (3): - determnaton of the source free velocty (so-called stage 2): Two methods have been consdered: - drect measurement of the free velocty at the source feet wth the possblty of usng standard ISO 9611 (source mounted on reslent mounts) - use of a thn recepton plate wth the possblty of usng the plate defned by the ISO TC43SC1WG22 group source v free v source reslent mount aboratory setup (stage 2) thn recepton plate Euronose 09, Ednburgh, Cost FP0702 October workshop, 2009 Delft, November 2010 PAGE 10

11 concluson Predcton of sound levels from servce equpment very new: - standard for predcton method: EN : standard for laboratory characterzaton of sources: EN : stll lmted to heavy recevers - stll very few data avalable (source arborne and structure borne sound power) - need for feld valdaton work under way for tmber based lghtweght recevers - to estmate the source characterstcs (free velocty and moblty) - to estmate the nstalled power for any source recever condtons - to predct the nose generated n buldngs Euronose 09, Ednburgh, October 2009 PAGE 11