- Library Home /
- Search Collections /
- Open Collections /
- Browse Collections /
- UBC Theses and Dissertations /
- Friction induced vibrations in a hydraulically driven...
Open Collections
UBC Theses and Dissertations
UBC Theses and Dissertations
Friction induced vibrations in a hydraulically driven system Johannes, Veikko Ilmari
Abstract
A study has been made of the behaviour of a hydraulic-ally driven system subject to friction induced oscillations. An experimental apparatus consisting of a heavy mass driven by a hydraulic ram was constructed. A mathematical model for the system was derived, and its validity was shown by comparison with experimental results. Studies were subsequently carried out with the mathematical model to determine the effects of varying system parameters and to verify the validity of simplifications in the governing equations. It was found that in general the effect of leakage at the piston should be negligible, and that the variation in behaviour with piston location can be predicted by a simple system stiffness correction. The effect of changing most parameters is to change the rate of tangential load application for a given average velocity of traverse, and the resulting behaviour can be predicted from the static friction relationship that has been proposed. A detailed study was made of the nature of the friction forces in effect during a stick-slip process. A relation, for the variation of the static coefficient of friction which appears more accurate than previous time of contact dependent formulations has been found. In the case of the kinetic coefficient of friction, a gradual decrease from the static value was found at the inception of slip. This has been observed before but generally it has not been recognized by investigators of stick-slip. Simple models have been given for both the static and kinetic friction behaviour. These may be useful as guide in further research into the fundamental nature of friction.
Item Metadata
Title |
Friction induced vibrations in a hydraulically driven system
|
Creator | |
Publisher |
University of British Columbia
|
Date Issued |
1969
|
Description |
A study has been made of the behaviour of a hydraulic-ally driven system subject to friction induced oscillations.
An experimental apparatus consisting of a heavy mass driven by a hydraulic ram was constructed. A mathematical model for the system was derived, and its validity was shown by comparison with experimental results. Studies were subsequently carried out with the mathematical model to determine the effects of varying system parameters and to verify the validity of simplifications in the governing equations.
It was found that in general the effect of leakage at the piston should be negligible, and that the variation in behaviour with piston location can be predicted by a simple system stiffness correction. The effect of changing most parameters is to change the rate of tangential load application for a given average velocity of traverse, and the resulting behaviour can be predicted from the static friction relationship
that has been proposed.
A detailed study was made of the nature of the friction forces in effect during a stick-slip process. A relation, for the variation of the static coefficient of friction which appears more accurate than previous time of contact dependent formulations has been found. In the case of the kinetic coefficient
of friction, a gradual decrease from the static value was found at the inception of slip. This has been observed before but generally it has not been recognized by investigators of stick-slip.
Simple models have been given for both the static and kinetic friction behaviour. These may be useful as guide in further research into the fundamental nature of friction.
|
Genre | |
Type | |
Language |
eng
|
Date Available |
2011-05-19
|
Provider |
Vancouver : University of British Columbia Library
|
Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
|
DOI |
10.14288/1.0101980
|
URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
|
Campus | |
Scholarly Level |
Graduate
|
Aggregated Source Repository |
DSpace
|
Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.