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Overall interior noise design tool for road vehicles


Objectives and content
The release of every new vehicle requires extensive and
complex refinement in order to reduce noise levels and to
reach acoustic comfort acceptable to car buyers. The
acoustic performance is the overall result of complex
interactions between many factors, such as different
sources (engine, road, aerodynamics), mixed solid and non
solid transmission paths for vibrations, coupling between
fluid and structures and finally type and quality of
vehicle trimming.
The final vehicle objectives are normally reached through
intensive experimentally driven prototype tuning
resulting in large costs, long duration, and large number
of prototypes. The limited capability to anticipate
analyses during the concept phase often makes it
difficult to timely implement the required modifications
to the vehicle with the result of non-optimal use of the
materials and increased weight.
Reliable numerical predictions are actually feasible only
for limited aspects of the problem, such as the noise
generated by the engine and transmitted to the passenger
compartment through the structure (structure-borne).
Methods are still lacking for other sources (tire-road
and aerodynamics), for the transmission paths through air
(airborne) and for simulating the full trim.
The inadequate link between state-of-art predictions and
the real behaviour and the difficulty to translate the
performances at the vehicle level into specifications at
the component level affect the possibility to implement
effective vehicle pre-optimisation for noise during the
concept phase.
In addition, the trend to reduce the vehicle weight (20-
40% in view of the forthcoming restrictive fuel
consumption constraints in the EU, the US and Japan),
while complying with future standards regarding passive
safety, could lead to new technologies, materials and
vehicle architectures potentially conflicting with
increasing customer expectations concerning noise and
vibration comfort.
The substantial amount of product innovation in the
presence of severe time-to-market and cost constraints
motivate the need for a step forward in specific
engineering methodologies. Due to the complexity of
technical and technological problems and know-how
involved, such envisaged developments need to be
addressed and validated by the end users.
The proposed project intends to develop an engineering
procedure based on the FEM-FSI (Finite Element Method -
Fluid-Structure Interaction) technique in order to
support the acoustic design of new vehicles from the very
first phases of project development, addressing the main
acoustic sources, i.e. engine, road and aerodynamics, as
well as structure-borne and air-borne transmission paths.
In the context of this project, the term engineering
procedure is meant as an easy-to-use, integrated set of
robust software tools and designer-oriented modelling
criteria, mainly for the first design phases.
In synthesis, technical objectives and the related
developments of this proposal are:
to extend state of art boom noise predictions (0-200
Hz) by introducing:
interior noise caused by the external aerodynamic field
noise emitted by the engine and transmitted through the
air in the engine compartment airborne)
interior noise generated by the tire-road interaction
to develop suitable models of vehicle trimming
to integrate CAE tools for vehicle structures,
passenger compartment cavity, and engine. external
to demonstrate the feasibility and related benefits
through real case studies.
The final results will be a prototype SW enabling
designers to predict the overall interior noise within a
vehicle, case studies demonstrating the feasibility to
manage vehicle and trimming modifications, models and
material databases of acoustic trimmings.
The proposed approach could be extended to all
applications in the ground transportation field, with
limited modifications for the commercial vehicles and the
public transportation. More extended modifications, such
as the redefinition of the road-wheel noise source and
the specific trimmings, would be required for the railway
industry that however would take particular benefits from
applying the methodologies to predict the aerodynamic
noise mainly to the high-speed trains.
The consortium comprises three car manufacturers (two of
whom are associated), with complementary expertise and
products, strongly committed with the development of
innovative vehicles, that will act as final users as well
as developers of FEM modelling criteria for full vehicle
simulation bringing their to the development of the new
methodologies, an industrial research and technological
development organisation with a consolidated experience
in the applied research for vehicle development that will
develop and validate the engineering methodologies and,
finally, a supplier of sound-proofing material that will
be involved in the characterisation and modelling of the
acoustic trimming.

Funding Scheme

CSC - Cost-sharing contracts


Centro Ricerche Fiat SCpA
Strada Torino 50
10043 Orbassano Torino

Participants (7)

Audi AG
Auto Union Strasse
85045 Ingolstadt
Avenue Guy De Collongue 36
69131 Ecully
GIE PSA Peugeot Citroën
18,Rue Des Fauvelles 18
92252 La Garenne-colombes
Rieter Automotive Fimit SpA
Via G. Agnesi 251
20033 Desio Milano
United Kingdom
Place Cottage, 1 The Green, Chilton
OX11 OSD Didcot, Oxfordshire
Technische Universität Berlin
Einsteinufer 25
10587 Berlin
Volkswagen AG

38436 Wolfsburg