Machines Elements

Base Knowledge

Previous knowledge in the areas of Physics, Mathematics, Strength of Materials and Applied Mechanics.

Teaching Methodologies

  • In theoretical classes, topics corresponding to the syllabus of the discipline are presented and developed in order to promote the continuous participation and discussion of the subjects with the students, stimulating their critical analysis.
  • Theoretical-practical classes are essentially oriented towards concepts’ application in order to solve real problems. In these classes it is sought that the student have an active participation by suggesting alternative strategies to solving the proposed problems, thus increasing their skills in the design and selection of machine elements that make up the majority of mechanical and electromechanical equipment.

Learning Results

It is intended that students acquire fundamental knowledge for the design and/or selection of machine elements. For that, after introduction, concepts, procedures and calculation methodologies involved in the selection and dimensioning of machine parts and structural elements are taught. At the end of this course unit, it is expected that students be able to apply the main concepts of static design and fatigue design.

Program

1. Introduction to the design of mechanical elements.
General characteristics of mechanical transmissions. Types. Comparative analysis of different types of mechanical transmissions. Transmission selection factors.
2. Flexible mechanical transmissions.
Types. Specific features. Comparative analysis of different types of flexible transmissions. Applications.
3. Belt drives.
Types of belts: flat, trapezoidal and toothed. Specific applications. Comparative analysis of different types of belts. Geometry and nomenclature. Selecting the transmission. Construction and assembly details. Types of ruin. Dynamic study.
4. Chain drives.
Nomenclature and geometric relations. Kinematic analysis. Selecting the transmission. Assembly and maintenance. Analysis of requirements. Dynamic study.
5. Rigid mechanical transmissions: gears.
Introduction. Classification of gears. Fundamentals. Cylindrical spur gears and helical gears: basics; basic law of engagement. Terminology of sprockets. Classification of gears. Geometric relations. Gear profile by envelope: analysis and construction. Carving the sprockets. Continuity of action. Cutting and operating interferences. Kinematics of gears. Loads on teeth. Loads on shafts and supports. Dynamic study. Dimensioning by ISO standards. Dimensioning at break and surface pressure.
6. Shafts.
Introduction. Sizing of shafts using the ASME code.
7. Fatigue.
Concept of fatigue. Characterization of the fatigue process. Typical forms of fatigue rupture. Phenomenological laws of behaviour to fatigue. Finite and infinite life. Fatigue tests. Fatigue resistance limit. Correction of the fatigue resistance limit: determination of the main parameters that affect the fatigue resistance of a given component. Sizing of shafts to fatigue.
8. Bearings.
Concepts and nomenclature. Bearings’ features and components. Types of bearings. Static load capacity and bearing dynamics. Equivalent bearing load. Bearings’ life. Calculation of nominal life. Rotation limits. Friction. Applications. Lubrication and assembly. Selection and sizing of bearings.

Curricular Unit Teachers

Internship(s)

NAO

Bibliography

Recommended Bibliography:
[1] MALÇA, C. (2022). Órgãos de Máquinas – Diapositivos de apoio às Aulas Teóricas da unidade curricular. ISEC (disponível na plataforma académica InforEstudante)
[2] MALÇA, C. (2022). Órgãos de Máquinas – Diapositivos de apoio às Aulas Teóricas-Práticas da unidade curricular. ISEC (disponível na plataforma académica InforEstudante)
[3] BRANCO,C.M., FERREIRA, M., COSTA, J., RIBEIRO, A. (2005), Projecto de Órgãos de Máquinas, Lisboa: F.C. Gulbenkian, (disponível na Biblioteca do ISEC)
[4] J SHIGLEY, E. (1977), Mechanical Engineering Design, Tokyo: McGraw-Hill Kogakusha, (disponível na Biblioteca do ISEC)
[5] J BUDYNAS, R.G., NISBETT, J.K. (2008), Shigley’s mechanical engineering design, Singapore: McGraw-Hill, (disponível na Biblioteca do ISEC)
[6] BRANCO, C.M. (1998), Mecânica dos Materiais, Lisboa: F.C. Gulbenkian, (disponível na Biblioteca do ISEC)

Complementary Bibliography:
[7] MOTT R.L. (2003), Machine Elements in Mechanical Design, Prentice Hall.
[8] SHIGLEY, J. E., MISCHKE,C. R.,  BUDYNAS, R. G. (2004),  Mechanical Engineering Design, Mc Graw-Hill.
[9] HIBBELER, R. C. (2005), Dinâmica: Mecânica para Engenharia, Prentice Hall.
[10] NORTON, R.L. (2005), Machine Design, Prentice-Hall.
[11] HAMROCK, B., SCHMID, S., JACOBSON, B. (2007), Fundamental of Machine Elements, Mc Graw Hill.
[12] BUDYNAS, R. G., NISBETT, J. K. (2008), Shigley’s Mechanical Engineering Design, Mc Graw Hill.
[13] JUVINALL, R.C., MARSHEK, K.M. (1991), Fundamentals of Machine Component Design, John Wiley & Son.