Machine Elements I




Generic Description

The discipline aims to provide students with knowledge about dimensioning of components and basic mechanical systems.

To Know

Notion about screw thread. Attainment of a thread. Differences between common thread types and their application. Forces and stress distribution in threaded components.

Notion about riveted joints. Differences between common rivets types and their application. Forces and stress distribution in riveted joints.

Notion about welded joints. Forces and stress distribution in welded joints. But and fillet welding. Notion about bonded and soldered joints.

Notion about keyed joints. Differences between longitudinal and transverse keys. Differences between free and forced keys. Forces and stress distribution in keyed joints. Notion about pins and split pins. Differences between common types and their application.

Notion about spring. Differences between spring common types and their application. Notion about forces, stress distribution, deflection and geometrical variations in different types of springs. Springs stability.

Notion about clutches and brakes. Differences between clutches and brakes, common types and their application. Materials and linings for clutches and brakes.

Notion about belt drives. Differences between belts common types and their application. Belts materials. Influential factors for belt durability.

Notion about shaft coupling. Differences between shaft couplings, common types and their application.

Notion about rolling-contact bearing. Differences between bearings, common types and their application.

To Make

Calculate power screws and threaded joints.

Calculate riveted joints. Choose the joint configuration.

Choose a type of joint. Configure the joint. Calculate welded, bonded and soldered joints.

Choose a type of key or pin. Calculate joints with keys, pins and split pins.

Choose a type of spring. Calculate common types of springs.

Choose a type of clutches or brakes. Calculate common types of clutches and brakes.

Choose a type of belt and drive configuration. Calculate common types of belt drives.

Choose a type of shaft coupling. Calculate common types of shaft couplings.

Choose a type of bearing. Calculate common types of rolling-contact bearings.

Soft Skills

Technology and global development.

The knowledge of social and ethical implications of technology.

Technical writing.

Argumentation knowledge and methodology.



General characterization





Responsible teacher

Alberto José Antunes Marques Martinho, António José Freire Mourão


Weekly - 4

Total - 76

Teaching language



Students must have completed the Engineering Sciences (CE) and Mechanical Engineering (EMc) subjects of the 1st Cycle.


“Mechanical Engineering Design”, Joseph Edward Shigley & Charles R. Mischke, McGraw-Hill International Editions.
“Órgãos de Máquinas”, Luciano O. Faria, AEIST.
Desenho Técnico”; Veiga da Cunha; Fundação Calouste Gulbenkian.
- A. J. A. M. Martinho, Órgãos de Máquinas I. DEMI - FCT / UNL, 2011 (versão v31)

Teaching method

Presentation of theoretical contents followed by analysis of real problems and resolution of project cases, in an environment involving professor and students.

Evaluation method

The assessment includes tow tests (T1 and T2) and a final exam (E).

Continuous evaluation rating is obtained by the expression:

CC = (T1 + T2) / 2.

The final classification (CF)  is calculated by the expression:

CF = CC se CC >= 9.5  |   CF  =  E  se  CC < 9.5

Subject matter

 1)      Threaded elements: Attainment of a thread. Typical thread applications. Thread profiles. Tightening and untightening torque. Reversibility and efficiency of threaded pairs. Forces and stress distribution in threaded components. Standard classes for bolts and nuts. Calculation of threaded joints. Primary load, secondary load and total load. Bolt group centroid.

2)      Riveted joints: Standards for rivets. Stress distribution in riveted joints. Calculation of riveted joints.

3)      Welding: Critical welded area. Stress distribution in but and fillet welding. Calculation of welded joints. Norris and Salakian diagrams.

4)      Keyed joints: Longitudinal and transverse keys. Free and forced keys. Calculation of keyed joints.

5)      Pins and split pins.

6)      Bonded and soldered joints.

7)      Springs: Typical spring applications. Helical springs for extension and compression. Calculation. Stress distribution and deflection in helical springs. Compression springs stability. Calculation of helical springs for torsion. Stress distribution. Angular deflection and diameter variation. Calculation of Belleville washers. Calculation of volute springs. Calculation of leaf springs.

8)      Clutches and brakes: Calculation of disc and multi-disc clutches and brakes. Cone clutches and brakes. Internal and external expanding clutches and brakes. Oscillating shoes. Pneumatic devices. Band-type clutches and brakes. Lining materials for clutches and brakes.

9)      Belt drives: Calculation of flat-, V- and timing-belts. Belt materials. Influential factors for belt durability.

10)  Shaft couplings: Calculation.

11)  Rolling-contact bearings: Calculation.



Programs where the course is taught: