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|Title: ||Modelling the ultrasonically assisted turning of high-strength alloys.|
|Authors: ||Mitrofanov, A.V.|
|Issue Date: ||2004|
|Publisher: ||© A.V. Mitrofanov|
|Abstract: ||The thesis deals with a novel machining technique - ultrasonically assisted turning
(VAT)·- and its comparison with conventional turning (CT). The main objective of
the research is a detailed analysis of various features of both processes, especially the
deformational and thermomechanical behaviour of the treated material. The main
emphasis here is on the superalloy Inconel 718 due to the industrial demand.
A thorough analysis of the cutting techniques is possible only with the use of
advanced finite-element numerical simulations validated by a range of experimental
methods (mechanical, optical, microstructural and thermal). Various effects of
technological parameters (lubrication, thermal contact conditions, etc.) on
deformational processes, stresses and chip formation are studied.
High-speed filming of the cutter - workpiece interaction zone is conducted to
compare chip formation processes for both technologies. Light microscopy, scanning
electron microscopy (SEM) and nanoindentation analyses are employed to study the
differences in the microstructure of surface layers of machined workpieces. Cuttingforce
measurements and infrared thermography when turning with and without
ultrasonic assistance are also carried out.
The two-dimensional finite-element (FE) model is developed with MSC MARC
general FE code and provides a transient, fully coupled thermomechanical analysis
of both ultrasonic and conventional turning ofInconel 718. A detailed study of the
VAT process is performed, including specificity of the single cycle of ultrasonic
vibration. Differences between thermal and deformation processes for VAT and CT,
effects of application coolant/lubricant, various friction conditions, and specific
features of the heat conduction between chip and cutting tool are examined.
For the first time, thermomechanics of VAT has been thoroughly analysed. The
main outcome of the thesis is an in-depth understanding of the VAT process, and of
its advantages and disadvantages in comparison to CT. Recommendations on further
research development are also suggested.|
|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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