Contact Mechanics and Lubrication

Code:

EM0070

Acronym:

MCL

Keywords
Classification	Keyword
OFICIAL	Applied Mechanics

Instance: 2019/2020 - 1S

Active?	Yes
Responsible unit:	Applied Mechanics Section
Course/CS Responsible:	Master in Mechanical Engineering

Cycles of Study/Courses

Acronym	No. of Students	Study Plan	Curricular Years	Credits UCN	Credits ECTS	Contact hours	Total Time
MIEM	13	Syllabus since 2006/2007	5	-	6	45,5	162

Teaching language

Portuguese

Objectives

Behaviour and Design of lubricated mechanical components under contact - Gears, Rolling Bearings, Cams.

Learning outcomes and competences

To understand physical phenomena involved in the contact between surfaces in relative motion;

To be acquainted with the Hertzian mechanics contact theory, thermohydrodynamics lubrication and elastohydrodynamics lubrication;

To apply tribological criteria of conception and dimensioning of mechanical components (gears, rolling bearings, cams, ...) and to select an adequate lubricant;

To be capable of analysing surface failure and relate it with concepts of Contact Mechanics, and Hydrodynamic Lubrication and Elastohydrodynamic Lubrication.

 

Working method

Presencial

Pre-requirements (prior knowledge) and co-requirements (common knowledge)

Rigid Body Kinematics and Dynamics.

Solid Mechanics.

Machine Elements.

 

Program

Hertzian Contact Mechanics (8 classes, 14.0 hours):
Contact between solids of revolution (Hertz Theory), stress in the interior of solids in contact; influence of surface roughness on contact; applications.

Elastohydrodynamic Lubrication (7 classes, 12.0 hours):
Elastohydrodynamic lubrication theory; thickness of EHD lubricant film; rheology of EHD lubricant film; thermal elastohydrodynamic contact; applications.

Lubrication, efficiency, gear failure (6 classes, 12.5 hours):
Tribological Contact between teeth of a cylindrical gear; energy balance of a gearbox; types and methods of gear lubricants; bearing surface, gears and bearings failures; lubricant selection; applications.

Mandatory literature

Jorge Seabra; “Engrenagens – Lubrificação, Rendimento e Avarias”, SMAp, DEMEGI, FEUP, 1ª Edição, 104 páginas, 2005
Jorge Seabra, Armando Campos e Alexandre Sottomayor; “Lubrificação Elastohidrodinâmica”, SMAP, DEMEGI, FEUP, 1ª Edição, 200 páginas, 2002
Ferreira, Luís António de Andrade; Tribologia. ISBN: 972-95794-5-8
Jorge Seabra; “Problemas propostos, Formulário, Folha de Cálculo e Aplicações MatLab em Mecânica do Contacto e Lubrificação Elastohidrodinâmica”, SMAP, DEMEGI, FEUP, 3ª Edição, 112 páginas, 2005
Jorge Seabra; “Mecânica do Contacto Hertziano”, 3ª Edição, 138 páginas., SMAp, DEMEGI, FEUP, 2003

Complementary Bibliography

Gohar, Ramsey; Elastohydrodynamics. ISBN: 0-85312-820-0
KLUBER Lubrication; Lubrication of gear systems – From large to small stationary gear sets, Kluber Lubrication Munchen KG, Germany, Edition 12.98, 84 pp., 1998
Boresi, Arthur P.; Advanced mechanics of materials. ISBN: 0-471-55157-0
Hamrock, Bernard J.; Fundamentals of fluid film lubrification. ISBN: 0-07-113356-9
Johnson, K. L.; Contact mechanics. ISBN: 0-521-25576-7
Dowson, D.; Elasto-hydrodynamic lubrification. ISBN: 0-08-021303-0
J. Ayel; Introduction à la lubrification des engrenages, em La Lubrification Industrielle - Tome 1 – Transmissions, Compresseurs, Turbines, pp. 185 – 296, Publications de L’Institut Français du Pétrole, Éditions Technip, Paris, 1984. ISBN: 2-7108-0471
G. Henriot; La Lubrification des engrenages, em La Lubrification Industrielle - Tome 1 – Transmissions, Compresseurs, Turbines, pp. 185 – 296, Publications de L’Institut Français du Pétrole, Éditions Technip, Paris, 1984. ISBN: 2-7108-0471

Teaching methods and learning activities

Theoretical classes with program exposition and discussion (26 hours);

Practical classes with problem solving and case discussion (12.5 hours);

Laboratorial tests (20 hours, extra-curricular);

Distributed Assessment (4 hours, extra-curricular)

Evaluation Type

Distributed evaluation with final exam

Assessment Components

Designation	Weight (%)
Teste	67,00
Trabalho escrito	21,00
Trabalho laboratorial	12,00
Total:	100,00

Amount of time allocated to each course unit

Designation	Time (hours)
Elaboração de relatório/dissertação/tese	30,00
Estudo autónomo	76,00
Frequência das aulas	38,00
Trabalho laboratorial	20,00
Total:	164,00

Eligibility for exams

Students can attend the final exam only if they achieve a grade of 10 (ten) out of 20 in the Distributed Assessment.
Military personnel, working students and Student Association members included.

Calculation formula of final grade

Distributed Assessment (DA)
Distributed Assessment is divided into two components: exams and homework:
- Exams (E1, E2) - two written exams during the semester. Each of the exams will be based on a theoretical part (to consult notes is not allowed – a 12 out of 20, 75 minutes) and a practical part (a 8 out of 20, 60 minutes)
- Homework (HW) - exercises given during classes should be done as homework. Students should give them back to the Professor in order to be corrected (they will be graded with a mark from 0 to 20).
- Students can attend the final exam only if they achieve a minimum grade of 8 (eight) out of 20 in the Distributed Assessment. Military students, working students and Student Association members included.
- Students who achieve a minimum grade of 12 (twelve) out of 20 in the Distributed Assessment are not obliged to attend the exam.

Final Exam (FE)
A written exam based on a theoretical part (closed book exam- a 12 out of 20, 60 minutes) and a practical part (open book exam and 8 out of 20, 60 minutes)

Final Mark (FM)
Final Mark will be calculated as follows: 40% of the Distributed Assessment plus 60% of exam grade: FM= 0.4xDA+0.6xFE
Students who do not want to attend to the final exam will have the grade that they have achieved on Distributed Assessment.

Examinations or Special Assignments

First test- 25 October 2017, 17h00-19h30.
Second test- 06 December 2017, 17h00-19h30.
Homework (HW).

Special assessment (TE, DA, ...)

Only students who have achieved a minimum grade of 8 (eight) out of 20 on the Distributed Assessment can attend the exam.
Military personnel, working students and Student Association members included.

Classification improvement

Students who want to improve their grade will have to do either one component of assessment or both components (Distributed Assessment or Final Exam).

Observations

Not applicable