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|Title: ||The analysis of ultrasonic machining systems using wholefield interferometric techniques|
|Authors: ||Petzing, Jon N.|
|Issue Date: ||1996|
|Publisher: ||© J. N. Petzing|
|Abstract: ||High power ultrasonic machining components and systems have been developed during
the last forty years, but have not achieved an accepted place in the industrial environment.
This has been a factor of competing traditional machining techniques which offer
consistent performance, as opposed to ultrasonic equipment which has limited theoretical
background and poor reliability. Niche applications involving polymer welding have been
secured, but the ultrasonic equipment in these cases is very simple in form, generally being
composed of three components; a transducer, a velocity transformer and the welding tool.
Interest in ultrasonic machining is being expressed by certain manufacturing companies,
which demand more complex systems, with as many as twenty ultrasonic components.
However, design and operation of these systems using traditional methods have not been
systematic, and there has been a requirement for improved analytical approaches and
design rigour and design validation.
The research described within this thesis is concerned with the novel analysis,
understanding and design of high power ultrasonic cutting systems for the food industry.
The operational behaviour of individual resonant components, sub-assemblies and
complete cutting systems have been examined, in order to determine how design boundary
conditions may be altered, such that the performance of the cutting system is improved
or optimised. Analysis of experimental data produced by single point, wholefield optical
techniques, and software based models (produced via Finite Element Analysis), have
allowed the introduction of new designs of cutting system which achieve better cut quality
parameters than original equipment.
A major component of the research has been the evolution of new experimental techniques
employed for the ultrasonic analysis. Recent work in this area had shown the applicability
of Electronic Speckle Pattern Interferometry (ESPI), but was found to have limited range
and sensitivity in industrial operating conditions. Questions of detail concerning the linear
or non-linear behaviour of the ultrasonic cutting systems at high powers whilst cutting
material, in comparison to low power laboratory investigations, generated the
fundamental requirement for analysis in the industrial environment. Therefore it was
necessary to evolve the wholefield techniques to answer these questions. Novel
experimental techniques have been developed and applied in the form of Electronic
Speckle Pattern Shearing Interferometry (ESPSI), for the analysis of low and high
amplitude dynamic displacements. The versatility and simplicity of this technique has
allowed the examination of ultrasonic phenomena from low power to high power
excitation, thus providing a gauge of the linearity of the cutting systems behaviour.
The novel application of speckle shearing interferometry has been extended to the analysis
of ultrasonic and sonic components in harsh, arduous industrial conditions, obtaining
interferometric data of unprecedented quality. This has centred around the ultrasonic
cutting systems during cutting trials of various confectionary products, and a minor
examination of f1extensional sonar transducers whilst operating in large scale underwater
testing facilities. The success of this work has been made possible by the use of pulsed
lasers within the interferometers, and the integration of the interferometric systems with
laser vibrometer synchronisation.
A final aspect of the research has been to consider the interaction of the ultrasonic cutting
systems with the materials being machined. This has required further development of
speckle shearing interferometry in order to investigate and utilise its ability to measure
out-of-plane and in-plane strain values.|
|Description: ||A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.|
|Appears in Collections:||PhD Theses (Mechanical, Electrical and Manufacturing Engineering)|
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