Identifier

etd-08142008-163923

Degree

Doctor of Philosophy (PhD)

Department

Mechanical Engineering

Document Type

Dissertation

Abstract

Surface heating by application of a moving heat source is a common problem in most manufacturing processes as well as in many tribological applications. The existing literature on studies of moving heat source problems primarily concentrates on unidirectional moving heat sources. Yet, a more complete analysis requires understanding of thermal behavior of bodies in relative sliding contacts subjected to oscillatory heat sources and thermomechanical interaction. In this dissertation, two analytical models are developed for rapid evaluation of the transient temperature in solids undergoing oscillatory heat source. In the first model, an analytical technique is presented to treat oscillatory heat source problems by using the Duhamel theorem. An explicit analytical solution for temperature variation in a rectangular domain subjected to oscillatory heat flux is developed. In the second model, the solutions for distributed heat sources undergoing oscillatory motion on the surface of a semi-infinite body are developed. The appropriate governing equations for different heat sources are derived and an efficient algorithm is developed to solve them. Finally, analytical expressions are provided for predicting maximum surface temperature. Two computationally-efficient algorithms are developed to handle complex transient moving heat source problems based on transfer matrix method combined with the dual reciprocity boundary element and finite element methods. The time integration is processed by an iteration transfer matrix method, making both models numerically stable. For the model associated with boundary element method, the domain integrals due to transient heat transfer are converted to a boundary one by the dual reciprocity method. The influence matrices are evaluated by an adaptive precise time integration method. In the analysis of oscillatory contacts, it is further necessary to take into consideration the thermomechanical interaction between the contact bodies. To this end, thermomechanical models are developed that enable one to efficiently treat such computationally demanding problems. The thermomechanical coupling process involves a transient solution scheme where the frictional heat is automatically partitioned between contact surfaces. The coupling between thermal and mechanical interaction is treated by an iteration method. In addition, a three dimensional computational model is presented. The numerical results are verified by the experimental measurements.

Date

2008

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

Micheal M. Khonsari

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