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An investigation relating to the design parameters of diaphragm mandrels

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posted on 2017-08-23, 14:29 authored by J. C. L. F. da Silva
The aim of the present investigation was to establish the equations relating the deformations and the gripping pressure of diaphragm mandrels, as well as to simplify them, enabling their utilization by a designer. Diaphragm mandrels, to be used in lathe or finishing machining work, can be seen as revolution pieces constituted of an assemblage of elastic elements disposed around their revolution axis. The centering and gripping operations rely only on the elastic forces generated when those elements are elasticly deformed. The non-existence of metalic sliding parts distinguishes this type of mandrels from the usual types and assures an high degree of repeatability and accuracy during the machining operations. Four fundamental stages constitute the present work. Firstly, the preliminary design of the geometrical shape for the diaphragm mandrels has been developed in chapter 2. The second and third fundamental stages have been undertaken simultaneously. They are constituted of an theoretical and experimental analysis in view to obtain the equations earlier refered. This analysis has been undertaken firstly on two different types of Specimen, simulating the constituting elements of a diaphragm mandrel and finally on a third Specimen simulating an actual section of the mandrel. The first Specimen simulated the tapered parts of the mandrel, and the second type simulated the assemblage of those tapered parts and the holding part in between them. On pages 42, 71 and 126 are represented the first, the second and the third type of those Specimen, respectively. In chapter 3 is elaborated the theoretical analysis of the first type, in chapter 7 the second type and in chapter 11 the third type. Their experimental analysis is presented on chapter 4, 5 and 6 for the first type, on chapters 8, 9 and 10 for the second one and on the chapter 12, 13 and 14 for the third type. The theoretical analysis, based upon the energy method enabled the calculations of deformations, load forces and gripping pressure relationships, and from the experimental work the experimental values have been obtained and used to verify the accuracy of the theoretical analysis. Mechanical and electronic techniques have been used during the experiments and close correlation between the predicted results and the experimental ones have been obtained, this being stated in chapter 6, chapter 10 and chapter 14. Finally the third stage of this investigation has been related with the simplification of the theoretical expressions and their presentation in a tabled way providing their use by a designer to characterize the behaviour of a mandrel as well as to define its geometrical dimensions under a specific work situation, chapter 17 and 18.

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Rights holder

© J. C. L. Ferreira da Silva

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Publication date

1982

Notes

A Masters Dissertation, submitted in partial fulfilment of the requirements of the award of Master of Science of Loughborough University.

Language

  • en

Qualification name

  • MSc

Qualification level

  • Masters

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    Mechanical, Electrical and Manufacturing Engineering Theses

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