Identifier

etd-11152007-095442

Degree

Doctor of Philosophy (PhD)

Department

Mechanical Engineering

Document Type

Dissertation

Abstract

This research deals with an experimental and numerical investigation of the frictional and thermal behavior of pin-bushing pairs, operating at reciprocating sliding motion or under heavy loads. Large interfacial temperatures developed due to frictional heating can cause failure. Therefore, numerical prediction and analysis of the surface temperature under various operating conditions are important. Laboratory tests using a pin-bushing tester provided measurements of the friction coefficient and temperature. Hard coated and plain (uncoated) bushings, both made of induction hardened stainless steel, were tested. Lower coefficient of friction and surface temperature were observed in the case of the coated bushing. In the modeling of the thermal problem, classical contact theory was used and a quasi-three-dimensional thermal model was developed and expressed by a set of partial differential equations and boundary conditions. Convective terms in the heat equation are handled by upwinding. This aspect of the computational model is important as it allows accurate solutions at high sliding velocities in concentrated contact. The boundary condition at the pin-bushing sliding interface is expressed as a mixed formula of heating and cooling, both of which can be space and time dependent. In most published literature dealing with surface temperature prediction, the heat flux is assumed uniform, and regions outside the contact are assumed to be adiabatic for simplicity. This aspect of the research is important and contributes to the field. Heat partitioning at the contact interface is computed as part of the solution. The method relies on coupling conditions at the interface, the material properties, and the solution gradients with respect to the normal direction at the interface. The effect of sliding is incorporated into the calculations. This is important in Tribology if it is desired to investigate heat flux division at contact interface for any material combination and sliding velocity. The results can be used in design and material selection in many applications where the heat flow within conducting bodies is to be controlled. Factorial analysis of variance was used to study the thermal response at steady state. This technique has not been applied previously to the analysis of surface temperature in pin-bushing joints.

Date

2007

Document Availability at the Time of Submission

Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.

Committee Chair

Michael M. Khonsari

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