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A new technology for vibration measurement of stationary and moving structures using scanning laser doppler velocimetry

Objective



Objectives and content
This project seeks to develop an exciting and powerful
new vibration measurement technology based on the use of
the scanning laser Doppler velocimeter (SLDV).
Development of the methods described in this proposal
will enable structural vibrations to be measured in
situations where it is extremely difficult or impossible
to function today. Of particular importance are the
situations where vibration measurements are required on
moving structures - such as components of rotating
machines, or of parts of a moving vehicle. Very elaborate
and expensive methods must be employed at present, which,
even then, provide only a limited amount of the
information sought. The new scanning laser based methods
will provide dramatic new opportunities in this important
area.
The seeds of the proposed research originated in earlier,
industrially based, projects which were concerned with
the effects of machinery vibration on noise and
reliability performance. Here, it is proposed to focus on
the development of this new technology as a central
objective, and to demonstrate its effectiveness on a
series of different applications, which are linked by the
common thread of all deriving from the automotive sector.
The basis of the proposed technology is the effective
exploitation of the scanning feature of the SLDV. In the
past, this scanning capability has been used simply to
automate the collection of vibration measurements at a
large number of points. No use has been made of the scan
as an independent and controllable parameter. However,
this feature can greatly enhance the potential of the
instrument. Introducing the scanning parameter as an
independent variable is equivalent to adding another
dimension to the measurement process.
The research seeks to develop this basic concept into a
series of different measurement tasks, including:
simultaneous measurement of several response degreesof-freedom at a point;
measurement of spatial variation in vibration amplitude
as continuous functions of position (instead of at a
sequence of discrete points);
combination of the scanning laser with mirrors and
fibre optics to extend the range of applicability to
points which do not have a direct line-of-sight to the
laser, and
use of the scanning control to track the motion of
rotating or arbitrarily-moving structures in order to
measure vibration superimposed on such movement
Successful development of these procedures would
constitute a major advance in the technology of vibration
measurement, leading to capabilities which give an orderof-magnitude increase in the quantity of good data
available, an order-of-magnitude decrease in the time
required for acquisition, and access to data which are
currently not measurable.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

IMPERIAL COLLEGE OF SCIENCE, TECHNOLOGY AND MEDICINE
Address
Exhibition Road
SW7 2BX London
United Kingdom

Participants (5)

Bridgestone / Firestone Technical Center Europe SpA
Italy
Address
Via Del Fosso Del Salceto 13-15
00129 Roma
Centro Ricerche Fiat SCpA
Italy
Address
Strada Torino 50
10043 Orbassano Torino
POLYTEC GmbH
Germany
Address
1-7,Polytec-platz 1-7
76337 Waldbronn
ROBERT BOSCH GMBH
Germany
Address
1,Robert Bosch Platz 1
70049 Stuttgart
UNIVERSITA POLITECNICA DELLE MARCHE
Italy
Address
Via Delle Brecce Bianche
60131 Ancona