Waves in fluid and solid media - Building Acoustics - page 101

4

ρ c c

∑ A

00 0

η = η + σ + .

kk

α (3.126)

total internal

2

π fm ⋅

π Sff ⋅

c

k = 1

The element has critical frequency f c (see section 3.7.3.1) and radiation factor σ for free
bending waves. The energy losses along the edges A k are characterized by an absorption
factor α k 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.