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Optimisation of Structural Connections for Noise and Vibration Reduction

Objective



Mechanical joints play a significant role in vibration
transfer and damping in structures, and therefore in
noise radiation. However, the development of the joining
technologies welding, riveting, bolting, bonding, etc.
has been always influenced by manufacturing and
structural integrity issues: as a consequence, these
technologies are not optimised for an efficient
vibration reduction.

The present day knowledge on vibration properties of
joints is largely insufficient to understand the behavior
of joints in mid frequency range (100 500 Hz) which is
the most important part of audible zone (highest ear
sensitivity) when typical mechanical structures like cars
or machines are concerned. Poor knowledge of transmission
and damping properties of joints forces industry to carry
out costly experimental work for optimising the shape,
location and volume of noise damping layers.

The project targets four industrial sectors: glass
industry, car manufacturers, domestic appliances and
engine driven machinery. Industrial objectives of the
project are:
To cut down by 20% noise transmission by existing
joints through optimisation of their implementation.
To increase the distributed damping produced by the
joints in complex structures, and consequently to reduce
by at least 20% the quantity of added damping materials
necessary for achieving given performance.
To reduce the spreading of noise emission of mass
products.
To reduce prototype development time and cost, by
creating realistic computation and experimental models.
To develop dissipative smart joints for increased
vibroacoustic performance.

This project is innovative at four levels:
1. New measurement and characterisation of joints alone
and embedded in structures:
Characterisation of single joints will be done by
using inverse and intensity techniques.
2 Coherent modelling techniques: Introduction of the
vibroacoustic characteristics of joints into
mathematical models will allow coherent modelling of
complex systems including joints.
3 Noise reduction efficient implementation of joints:
Influence of the implementation of joints on
vibration structural noise transmission and damping
effect will be extensively studied. Best
practice guidelines will be elaborated.
4 New smart joints: A particular innovative technology
using "smart joints" will upgrade the approach
to joint design in that the smart joints will provide a
dual role: structural integrity plus optimised
energy dissipation for noise and vibration
reduction.

The technological approach is based upon 6 main steps:
1. Setting industrial priorities by identifying joints
where a significative improvement can be expected.
2 Use of two specialised test rigs will allow fast
appraisal of performance of joints incorporated
into spacious thin wall structures
3. Simple smart joints will be optimised, and rules for
the design of such joints will be produced.
4. Test procedures will be developed for characterising
individual joints in industrial environment.
5. A set of rules for FE modelling of vibro acoustic
properties of traditional and smart joints will be
produced.
6. Industrial case studies will be performed for
experimental validation of the modelling
techniques assessment and evaluation of vibroacoustic
performance of joints. All results of the project
will be synthesised into industrial guidelines.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Saint-Gobain Vitrage
Address

60150 Thourotte
France

Participants (10)

AVL LIST GMBH
Austria
Address
48,Hans-list-platz 1
8020 Graz
CENTRE TECHNIQUE DES INDUSTRIES MECANIQUES
France
Address
52,Avenue Felix Louat 52
60300 Senlis
Centro Ricerche Fiat SCpA
Italy
Address
Strada Torino 50
10043 Orbassano Torino
Centro de Estudios e Investigaciones Técnicas de Guipuzcoa
Spain
Address
15,Paseo De Manuel De Lardizabal
20009 San Sebastian
EATEC LTD
United Kingdom
Address
Armstrong Court 3, Armstrong Way, Yate
BS37 5NG Bristol
Electrolux Research & Innovation AB
Sweden
Address
1,Luxbacken
105 45 Stockholm
REGIENOV - RENAULT RECHERCHE ET INNOVATION
France
Address
9,Avenue Du Golf 1
78288 Guyancourt
ROYAL INSTITUTE OF TECHNOLOGY
Sweden
Address
8,Teknikringen 8
100 44 Stockholm
Rieter Automotive Germany GmbH
Germany
Address
Im Mittelbruch
64380 Rossdorg
Sociedad Española de Automóbiles de Turismo SA
Spain
Address
Carretera Nacional Nii Km 585
08760 Martorell