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STRUCTURE BORNE INTENSITY TECHNIQUES FOR VIBRATION AND NOISE CHARACTERIZATION

Objective


The following results have been obtained:
- Codes for the extended SAI computation concerning general excitation and localised damping were developed. Also, an original computation technique based on the experimentally obtained modal data has been verified. The results show critical dependence of the SAI field on the quality of input structural data.
- Development and experimental verification of an in-plane Laser Doppler Velocimetry (LDV)-based sensor for SAI measurement. Very good measurement results have been obtained under laboratory conditions. The hardware developed potentially enables construction of the out-of-plane optical SAI sensor initially planned.
- Investigation of several procedures for Electronic Speckle Pattern Interferometry (ESPI)-based measurements for SAI wholefield reconstruction. In spite of initially encouraging results, the final achievements still lack conclusive results in view of significant influence of speckle noise on results.
- A novel procedure for the measurement of energy flow through resilient mounts has been developed. An error analysis and the associate experimental testing were successfully carried out. The procedure developed stands good chances to become applicable in real conditions.

- The theoretical basis for the adaptation of Principal Component Analysis to SAI measurements has been established. Initial measurements were carried out on simple structures for testing the validity of this approach. The results are encouraging but indicate that the combined SAI/PSA approach has to be used as a method complementary to other methods, not as an independent analysis tool.
The research proposed is aimed at introduction of novel measurement and computational tools to analysis of vibroacoustical transmission in structures. Major emphasis will be given to development of high-tech optical measurement techniques for quantitative visualisation of transmission phenomena through use of structure-borne acoustical intensity (SAI) concept. Programmes for improved predictive computation of SAI as well as a technique for measurement on vibroisolators will be realised in order to complete the technical potential of the new tools.

The principal research tasks are:

a) improvement of existing SAI computation techniques,
b) development of an optical method for point-wise SAI measurement on arbitrary objects,
c) development of an optical method for surface-wise SAI meaasurement on plane surfaces,
d) development of a method for measurement of vibroacoustical energy transmission through elastic elements,
e) development of methods for SAI data conversion for an enhanced analysis of transmission phenomena,
f) validation of developed techniques through comparison with other techniques.

The new techniques should result in industrial application in a 3 technical domains:

- vibration and noise reduction,
- dynamical stress measurement,
- vibroacoustical fault diagnostics.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Centre Technique des Industries Mécaniques (CETIM)
Address
52 Avenue Félix Louat
60304 Senlis
France

Participants (3)

LMS International
Belgium
Address
Interleuvenlaan 68
3001 Leuven
ROYAL INST OF TECHNOLOGY
Sweden
Address
Brinellvagen 28
10044 Stockholm
TU VIENNA
Austria
Address
Wiedner Hauptstrabe 8-134 Tu Freihaus
1040 Wien