Laboratory of Machine Elements and Machine Design




Author: Agouridas Konstantinos
Title: Complete three dimensional elastohydrodynamic lubrication under complex kinematics of general geometry bodies
Abstract: The present thesis deals with the problem of elastohydrodynamic lubrication (E.H.L.). Specifically, this work aims to the complete numerical simulation of elastohydrodynamic contacts. The thesis begins with an introduction to the subject, followed by historical review of the field of E.H.L. which covers the evolution of E.H.L. theory, the knowledge of lubricant properties and numerical methods applied on this problem. From this review, has been concluded that despite the important progress that has been made over the years, a general model for simulating E.H.L. is missing from the literature. The next step was the derivation of the governing equations of the problem. Goal of this process was to build a general mathematical model capable of describing the majority of cases of E.H.L. found in mechanical engineering applications. The mathematical model was properly non-dimensionalized and discretized. Continuing, numerical procedures applied to the discreet equations and an arithmetic model was developed. The reliability of the model was verified through comparison of its results with experimentally measured data. In order to point out the capabilities of the developed model several common and special cases of E.H.L. were simulated. The thesis concludes that for first time was presented a three-dimensional numerical general geometry model that can deal with E.H.L. and simultaneously includes in the solution process all the following features that affect the contact. Surface micro-structure, roughness, Misalignment errors, Starved lubrication, Thermal analysis, Transient solution, Complex contact body kinematics, Complete oil properties model, all the following properties are taken into account, viscosity, density, special heat capacity, thermal conductivity, rheological laws


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