Machine Elements

Code:

L.EM027

Acronym:

OM

Keywords
Classification	Keyword
OFICIAL	Applied mechanics

Instance: 2024/2025 - 2S

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

Cycles of Study/Courses

Acronym	No. of Students	Study Plan	Curricular Years	Credits UCN	Credits ECTS	Contact hours	Total Time
L.EM	252	Syllabus	3	-	6	58,5	162

Teaching language

Portuguese

Objectives

This course on the design of machine elements serves as a fundamental building block for the field of machine design. It covers the in-depth analysis and design of commonly used machine elements.

To successfully complete this course, students are required to have a solid understanding of related topics from other courses such as Solid Mechanics, Structural Mechanics, and Materials.

The knowledge and skills acquired in these courses will be applied and supplemented with the new concepts and techniques taught in this course.

Learning outcomes and competences

Upon completion of this course, students will have the ability to make informed decisions in the design and selection of machine elements.

Additionally, they will be able to apply analytical and other frameworks to the design of commonly used machine elements.

The course aims to provide both general and specific learning outcomes to give students a comprehensive understanding of the subject matter.

Working method

Presencial

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

To excel in this course, students should have a strong foundation in solid mechanics, structures, materials, technical drawing, and technological processes. Having a background in these areas will be essential for fully understanding and applying the concepts covered in this course.

Program

1 - Gears:
1.1 - Classification; criteria based upon axles and teeth; the case of parallel axes: spur and helical gears.
1.2 - The MAAG system for cutting gears; basic rack profile; involute.
1.3 - Metrology: base tangent length Wk; measurement over balls on external gears.
1.4 - Mating gears; contact ratio.
1.5 - Addendum modification; sliding; interference; imposed center distance.
1.6 - Introduction to load carrying capacity of gears.

2 - Fatigue design:
2.1 - Uniaxial and biaxial loading.
2.2 - Mean stress; Goodman and Soderberg.
2.3 - Stress concentration. The improvement of fatigue behaviour. The effect of residual stress fields.

3 - Tribology:
3.1 - Friction and wear.
3.2 - Lubrication laws; Reynolds equation.
3.3 - Lubricants' properties.
3.4 - Introduction to hydrodynamic and hydrostatic lubrication.
3.5 - Dry bearings.
3.6 - Elastohydrodynamic lubrication: Cheng's formulation for rolling bearings cam-follower and gears.

4 - Power transmission screws and fastening screws.

Mandatory literature

Henriot, Georges; Engrenages. ISBN: 2-10-003903-2
MAAG Gear Company, Ltd.; MAAG gear book
Ferreira, Luís Andrade; Tribologia. ISBN: 972-95794-5-8
Bernard J. Hamrock; Fundamentals of Fluid Film Lubrication, McGraw-Hill, 1994. ISBN: 0 07 025956 9
Branco, Carlos Augusto Gomes de Moura; Fadiga de estruturas soldadas. ISBN: 972-31-0139-4

Complementary Bibliography

Bernard J. Hamrock; Fundamentals of machine elements. ISBN: 0-07-111142-5
Branco, C. M., Ferreira, J. M., Costa, J. D., Ribeiro, A. S.; Projecto de Órgãos de Máquinas, Fundação Calouste Gulbenkian

Comments from the literature

Handouts, transparencies and some standards will be made available on course contents.

Teaching methods and learning activities

Lectures, tutorials and laboratory classes.
It is expected to include a seminar by external invited experts, with date to be appointed soon.

Software

Gear Calculation (https://github.com/cfernandesFEUP)
Roda2007.lsp
KISSSOFT AG

keywords

Technological sciences > Engineering > Mechanical engineering

Evaluation Type

Evaluation with final exam

Assessment Components

Designation	Weight (%)
Exame	90,00
Trabalho laboratorial	10,00
Total:	100,00

Amount of time allocated to each course unit

Designation	Time (hours)
Estudo autónomo	110,00
Frequência das aulas	52,00
Total:	162,00

Eligibility for exams

According to General Evaluation Rules of FEUP.

Calculation formula of final grade

Final mark in the course: X

Examination mark: Y

Laboratorial work mark: Z

Final mark calculation: X=0,9Y+0,1Z

A minimum classification of 9,50 in component Y is required to pass the course.
The classification of the laboratory component is obtained as follows: Z=(T1+T2+T3)/3
where T1, T2 e T3 correspond to the three laboratorial works with foreseen evaluation.
The laboratory assignments are compulsory. Students with TE status unable to attend the laboratory classes should seek an alternative solution with the professor in charge.

The exams are composed of a theoretical part without consultation (6 values) and a practical part (14 values) with a consultation.

Examinations or Special Assignments

Not applicable.

Internship work/project

Not applicable.

Special assessment (TE, DA, ...)

The special exams take place according to General Evaluation Rules of FEUP.

The exam of any special season is composed by a theoretical part without consultation (6 values) and a practical part (14 values) with consultation. The final classification of the course is the classification of the exam.

Classification improvement

According to General Evaluation Rules of FEUP.