Tribology

Code:

EM535

Acronym:

T

Instance: 2003/2004 - 1S

Active?	Yes
Responsible unit:	Applied Mechanics Section
Institution Responsible:	Faculty of Engineering

Cycles of Study/Courses

Acronym	No. of Students	Study Plan	Curricular Years	Credits UCN	Credits ECTS	Contact hours	Total Time
LEM	13	Plano de Estudos EM Oficial a partir de 2000	5	3,5	7	-
		Plano para Bachareis EM a partir 2000	2	3,5	7	-

Teaching language

Portuguese

Objectives

Theoretical analysis of the contact and lubrication between elastic solids of revolution.

Design and selection of rolling bearings, gears and cams considering the theories of contact mechanics and EHD lubrication.

Analysis of surface failures in EHD contacts and their relation with lubrication.

Program

CONTACT MECHANICS:
Introduction, Elastic half-spaces submitted to linear and point loads, Contact between solids of revolution (Hertz theory), Stresses inside contacting solids, Influence of surface roughness on contact pressures and stresses. Applications.

ELASTOHIDRODYNAMIC LUBRICATION:
Lubricants. Theory of elastohidrodynamic lubrication, lubricant film thickness and pressure distribution. Lubricant rheology and thermal behaviour of the EHD contact. Influence of surface roughness on EHD lubrication. Applications.

APPLICATIONS OF CONTACT MECHANICS AND EHD LUBRICATION:
Gears – Lubrication and surface failures(contact fatigue, scuffing and excessive wear). Rolling bearings – Lubrication, internal friction and surface failures. Contact fatigue in EHD contacts.

Main Bibliography

Course notes.

Summary of expressions used in Tribology (Contact mechanics and EHD Lubrication).

Excel Sheet for Tribology calculations.

Complementary Bibliography

Boresi and co-authors, "Advanced Mechanics of Materials", 3ª Edição, John Willey and Sons, New York, U.S.A., 1978 (ISBN-0-471-08892-7).

K. L. Johnson, "Contact Mechanics", Cambridge University Press, Cambridge, U.K., 1985 (ISBN-0-521-25576-7).

R. Gohar, "Elastohydrodynamics", Ellis Horwood Series in Mechanical Engineering, Ellis Horwood, Ltd, Chichester,U.K., 1988 (ISBN-0-85312-820-0).

D. Dowson and G. R. Higginson, "Elastohydrodynamic Lubrication", SI Edition, International Series on "Material Science and Technology", Pergamon Press, Oxford, U. K., 1977 (ISBN-0-08-021303-0).

B.J. Hamrock, "Fundamentals of Fluid Film Lubrication", Mcgraw-Hill International Editions, Mechanical Engineering Series, Mcgraw-Hill, Inc., New York, USA, 1994 (ISBN-0-07-113356-9).

Teaching methods and learning activities

Theoretical lessons - 34 hours.

Practical lessons - 12 hours.

Tests - 4 hours.

Software

Not applicable.

Evaluation Type

Distributed evaluation with final exam

Eligibility for exams

Frequency is attained if the students obtains a minimum classification of 95 points in the Continuous Evaluation.

Calculation formula of final grade

The final classification is equal to 40% of the Continuous Evaluation classification plus 60% of the Exam classification: FC = 0.4 x CE + 0.6 x EX .

Students that met the condition to waive the requirement for the Final Exam will have a final classification equal to the Continuous Evaluation classification.

Examinations or Special Assignments

Tests (T1, T2) - 2 written tests to be held on November 6 and December 18, 2003, without consultation, each one with a theoretical part (120 points) and a practical part (80 points), with a total duration of 1:45h and classified between 0 and 200 points.


HOMEWORK (HMW) – Set of problems proposed during the semester, to be solved after class and submitted for correction and classification between 0 and 200 points.

Special assessment (TE, DA, ...)

A minimum classification of 80 points in the Continuous Evaluation is mandatory for a student to be admitted to the final exam.
This condition is extensive to the "militares”, working students and “dirigentes associativos”.

Classification improvement

The improvement of the final classification implies the improvement of one or both of the evaluation components.