DAGA 2010 - Deutsche Gesellschaft für Akustik eV

48 DAGA 2010 Programm
The theory will be presented together with a number of in results have
validated by numerical simulation and measurement on various structures.
Mo. 14:40 Gauß B 554 Vorkolloquium Körperschall
Interface mobilities for structure-borne sound source characterization
and the description of the transmission process
H. Bonhoff und B.A.T. Petersson
TU Berlin, Institut für Strömungsmechanik und Techn. Akustik
The processing of measured or calculated source and receiver data
in order to obtain e.g. the transmitted power is currently performed by
means of the matrix formulation. In addition to the conditioning problems
of the matrix formulation in the presence of measurement errors, the
interpretation of the results can become cumbersome. With the introduction
of interface mobilities, the physical installation is subdivided into
a series of theoretical orders. Such interface orders are directly linked to
elementary vibrational characteristics such as the rigid-body motion and
consequently represent physically highly comprehensible quantities. As
it is demonstrated that the coupling between different orders is insignificant,
each order can be treated as an equivalent single-point and singlecomponent
system. With the gained formal simplicity in combination with
the physical transparency, the application of interface mobilities offers a
straightforward interpretation which is essential with respect to design.
The applicability of fast Fourier transform algorithms for the calculation
of the interface mobilities facilitates short computation times. A full set of
equations is presented for structure-borne sound source characterization
and the description of the transmission process by means of interface
mobilities.
Mo. 15:45 Gauß B 554 Vorkolloquium Körperschall
SB - Noise Control Design Rules and Rules of Thumb revisited by
numerical Experiments
K.-R. Kirchner und T. Kohrs
Bombardier Transportation
Noise Control Design Rules and Rules of Thumb are a kind of recipes
and valuable tools for the daily noise control by design process as well as
for trouble shooting tasks, even so they are rough procedures, practices
or guesstimates. A few of these rules are investigated (e.g. Lambda-
Half-Rule for Mass and Stiffness) in numerical experiments to show the
effect of the applied methods of SBN-reduction with regard to generation
(excitation), transmission and radiation. Therefore generic sources
(force, velocity) and transmission paths are treated in conjunction with
different receiving structures.