Building Acoustics

Waves in fluid and solid media 101

4

00 0

total internal 2

c 1

kk.

k

cc

fm Sff

ρ

η ησ α

π π =

=+ +

⋅ ⋅ ∑

A (3.126)

The element has critical frequency fc (see section 3.7.3.1) and radiation factor σ for free
bending waves. The energy losses along the edges Ak are characterized by an absorption
factor αk for bending waves. This factor may in a field situation be in the range 0.05 to
0.5. Further on we shall look into ways of estimating this factor.

3.8 References

EN 12354–1: 2000, Building acoustics – Estimation of acoustic performance of buildings
from the performance of elements. Part 1: Airborne sound insulation between
rooms.
ISO 3744: 1994, Acoustics – Determination of sound power levels of noise sources using
sound pressure – Engineering methods in an essentially free field over a reflecting
plane.
ISO 3746: 1996, Acoustics – Determination of sound power levels of noise sources using
sound pressure – Survey method using an enveloping surface over a reflecting
plane.
ISO 9614–2: 1996, Acoustics – Determination of sound power levels of noise sources
using sound intensity. Part 2: Measurement by scanning.
ISO 5136: 2003 Acoustics − Determination of sound power radiated into a duct by fans
and other air-moving devices – In-duct method.
ISO 80000–8: 2007, Quantities and units. Part 8: Acoustics. [At the stage of ISO/FDIS in
2007.]

Abramowitz, M. and Stegun, I. A. (1970) Handbook of mathematical functions. Dover
Publications Inc., New York.
Blevins, R. D. (1979) Formulas for natural frequency and mode shape. Van Nostrand
Reinhold Company, New York.
Buzzi, T., Courné, C., Moulinier, A. and Tisseyre, A. (2003) Prediction of the sound
reduction index: A modal approach. Applied Acoustics, 64, 793–814.
Hansen, C. H. (1993) Sound transmission loss of corrugated panels. Noise Control Eng.
J., 40, 187–197.
Kinsler, L. E., Frey, A. R., Coppens, A. B. and Sanders, J. V. (2000) Fundamentals of
acoustics, 4th edn. John Wiley & Sons, New York.
Mindlin, R.D. (1951) Influence of rotary inertia and shear on flexural motion of isotropic
plates. J. Appl. Mech., 18, 31–38.
Timoshenko, S. P. and Woinowsky-Krieger, S. (1959) Theory of plates and shells, 2nd
edn. McGraw-Hill, New York.