Antonis I. Vakis
Tribology is the study of interfaces in relative motion. The need to control friction is not new; however, its systematic study is relatively recent while its precise nature is still not fully understood. This course aims to introduce students to tribology – the study of contact, friction, lubrication and wear – starting from the traditional definitions and transitioning to recent theories and models used to understand the fundamentals of tribology and enable the design, analysis and optimization of devices over multiple scales.
Part of the course will deal with classical (macroscale) definitions and models of contact, friction and lubrication including, but not limited to:
› Hertzian contact and Coulomb friction;
› Hydrodynamic and elastohydrodynamic lubrication; and,
Example applications will be utilized to demonstrate these themes with analytical solutions as well as representative experimental and simulation results.
Subsequently transitioning to smaller scales, the course will look at the role of surface topography in contact and friction and investigate the importance of adhesion as a function of scale and roughness. Theories (and models) to be discussed are, for example:
› Short and long range atomic interactions;
› Roughness characterization (statistical, numerical, fractal);
› Sphere-on-flat models with adhesion (JKR, DMT, M-D);
› Rough surface models (Greenwood-Williamson, CEB, SBL);
› Other approaches (finite element-based models, molecular dynamics).
Brief descriptions of experimental methods will introduce students to the tools used in micro- and nanotribology, such as profilometry, atomic force microscopy (AFM) and nanoindentation. The course will also cover the coupling of tribology with dynamics and vibrations, especially in the micro- and nanoscale, via reviews of applications such as the head-disk interface of hard disk drives.
CAD/CAM is meant to serve as a bridge between the fundamentals learned in previous courses (e.g. “Materials Science and Engineering,” “Mechanics for TBK,” “Production Techniques”), and the comprehensive approach necessary for production management. Knowledge gained in this course will be further enhanced and applied in subsequent courses, including “Design and Construction for TBK” and the “BSc Integration Project.”
An overview of fundamental principles from materials science, mechanics, stresses, machine element design, failure theories, as well as conceptual design and visualization techniques, will be given during lectures, comprising primarily team work in computer laboratories to complete various projects: CAD, FEM, CAE and RP. In addition, the students will learn the principles behind CAM and attend CNC demonstration sessions. Students will work in teams to design, analyse and produce the parts necessary to create a prototype assembly as a final project, or reverse-engineer and reproduce an existing assembly.
Lectures will be interspersed throughout the laboratory sessions to introduce the concepts necessary for the computer projects, including technical drawing and the finite element method. Emphasis will be placed on the validation of FEM results with analytical theory. SolidWorks will be used for all computer laboratory sessions.
The lectures mainly treat materials of everyday life, such as metals, ceramics and polymers with an emphasis on mechanical and electrical properties. The red line throughout the lectures is the “triangular relationship” between structures, properties and processing of materials, e.g. from the process applied, the structure on various length scales from atomic to macroscopic scale can be predicted, and from the structure, the properties can be predicted. Knowledge and understanding of these relationships are important when designing with materials. In addition students will obtain basic skills (1) applying a method for optimum materials selection in product design (Cambridge Engineering Selector) and (2) performing finite element calculations (using linear elasticity theory) to analyze local stresses and strains present in materials with various geometries subjected to mechanical loading.
Copyright: Antonis I. Vakis, 2011-2017