 (115KB)
Transmission
loss assessment by integrated FEM-BEM methodology
C. Calì, R. Citarella, A.Galasso
Nowadays, one of the most valuable
criteria for vehicle quality assessment is based on
acoustic emission levels: a car is judged comfortable
also depending on the noise level transmitted inside.
Consequently there is a general attention to design
criteria aimed to improve the structural-acoustic behaviour
in such a way to withstand the increasingly restrictive
ergonomic standard. Such design approach, based on experimental
and numerical procedures, enables the prediction of
noise emissions and the correlation with the structural
vibration source. The following step is the redesign
of those components responsible for intolerable emissions,
without the need for an extensive and expensive prototyping
effort.
(988KB)
Application
of BEASY to industrial and environmental acoustics
S.M. Niku, R.A. Adey, T.R. Bridges
The analysis of acoustic problems is
becoming increasingly important, not only in the area
of automotive and aerospace industries where there has
been a demand to design quieter vehicles, but also because
noise pollution and noise control are becoming a sensitive
environmental issue. This paper highlights the application
and advantages of the Boundary Element Method in solving
acoustic problems. It also describes the details of
acoustic developments within the general purpose Boundary
Element Analysis System BEASY version 5. Some industrial
and environmental application examples are included.
(206KB)
Acoustic
diagnostic analysis of automobile passenger compartments
Y.K. Zhang, M.R. Lee, J. Trevelyan, R.A. Adey, S.M.
Niku, C.A. Brebbia
The automobile industry has long been
fiercely competitive, with different vendors attempting
to produce vehicles with better performance, handling
and fuel efficiency. Now the industry is seeing the
competition taking place in automobile acoustics, and
a quiet ride has become an important attribute of modem
vehicles. In order to assess the noise levels inside
a car, it is possible to analyze the acoustic field
using a computer based model. Most recently this has
been done predominantly using the Boundary Element Method
(BEM).
(498KB)
Acoustic
diagnostic analysis using Boundary Elements
R.A. Adey, S.M. Niku, J. Baynham, P. Burns
The prediction of sound levels in vehicles
and the environment is now a common practice in engineering.
This has been made possible by the development of powerful
tools based on boundary element techniques. These "first
generation" systems provided the user for the first
time easy to use tools to predict sound levels. This
paper will describe a “second generation”
acoustic system based on boundary elements which not
only enhances the accuracy of the modelling, but also
provides powerful diagnostic facilities to enable the
user to identify the main contributions to the sound
intensity at a any point of interest. Applications are
presented.
(498KB) Il
BEM nello Studio Acustico di un compressore
il Progrettista industriale, July 1998 (An Italian magazine report of an air
compressor modelled in BEASY - Acoustic)
Enrico Gargano and Alessandro Bartolini |
