Civil Engineering Reference
In-Depth Information
Trimmed floor panel configuration: Binappe carpet + Heavy layer 2kg/m
2
10 dB
Transmission Loss measurement bare
Transmission Loss Trim FEM simulation bare
Transmission Loss measurement trimmed
TL slope 12 dB/oct
Transmission Loss Trim FEM simulation trimmed
200
250
315
400 500
Frequency 1/3 oct (Hz)
630
800
1000
Figure 13.25
Example of model versus simulation of the transmission loss of a floor
panel with an absorption type trim (Duval
et al
. 2008).
describes the transmission loss case. An example of comparison between measurements
and simulations for the point-to-point pressure over force FRF (radiation case) are pre-
sented in Figure 13.23 and Figure 13.24. The simulations are very good, up to 700 Hz,
for both the absorption and insulation configurations. The correlation could have been
improved if the very thin decoupling air gaps between the felt and the heavy layer were
explicitly modelled (this is corroborated by systematic investigations on flat samples).
Figure 13.25 shows an example of comparison between measurements and simulations
of the transmission loss of the insulation configuration. Again, acceptable correlation
is observed. These examples demonstrate the good prediction of acoustic radiation and
transmission through the trims computed by FEM simulation, as well as the good predic-
tion of the damping induced by the trims to the structure. They also prove the importance
of good coverage and contact between the trims and the structure.
References
Anciant, M., Mebarek, L., Zhang, C. and Monet-Descombey, J. (2006) Full trimmed vehicle
simulation by using Rayon-VTM. JSAE.
Atalla N., Panneton, R. and Debergue, P. (1998) A mixed displacement pressure formulation for
poroelastic materials.
J. Acoust. Soc. Amer
.
104
, 1444 - 1452.
Atalla N., Hamdi, M.A. and Panneton, R. (2001a) Enhanced weak integral formulation for the
mixed (u,p) poroelastic equations.
J. Acoust. Soc. Am
.
109
(6), 3065 - 3068.
Atalla N., Sgard, F., Olny, X. and Panneton, R. (2001b) Acoustic absorption of macro-perforated
porous materials.
J. Sound Vib
.
243
(4), 659 - 678.
Atalla, N., Amedin, C.K., Atalla, Y., Sgard, F. and Osman, H. (2003) Numerical modeling and
experimental investigation of the absorption and transmission loss of heterogeneous porous
materials.
Proceedings of 10
th
International congress on Sound and Vibration
, ICSV12, pp
4673 - 4680.
