Base Knowledge
Knowledge in physics, mathematics, material resistance and applied mechanics.
Teaching Methodologies
In theoretical classes, the expository method is used. Content is exposed through the joint use of the whiteboard and PowerPoint presentations. Discussions about the contents presented are promoted. In the theoretical-practical classes, the problem-based learning method is used. The students solve in class type exercises where they make the application of the contents exposed in the theoretical classes.
Learning Results
Give a broad knowledge of the various mechanical components, and an introduction to the calculation and selection of mechanical components of some complexity, addressing the philosophy of mechanical design. Know the methods of dynamic project, bolted connections, springs and welded joints.
Program
1. Fatigue
Fatigue concept. Characterization of the fatigue process. Typical forms of fatigue failure. Variable and repeated load types. Phenomenological laws of fatigue behavior. Finite and infinite life. Fatigue resistance limit. Correction of the fatigue resistance limit: determination of the main parameters that affect the fatigue resistance of a given component. Fatigue tests and equipment. S-N curves and fatigue limit stress concept. Oligocyclic fatigue; Coffin-Manson law. Dimensioning for constant stress amplitude requests. Fatigue dimensioning for biaxial stresses of constant stress amplitude. Dimensioning for variable stress amplitude requests; Miner’s law. Dimensioning of fatigue shafts (Soderberg’s solution; Effect of stress concentration; Shaft shaping of deformation). Materials used in the shafts.
2. Screws and Bolted Joints
Introduction. Types of screws. Concepts and Nomenclature. Movement or power transmission screws (spindles): Forces, torques and applied stresses. Connection screws: effect of the existence of preload / pre-tension. Movement screws. Bolted joints: Resistance of bolted connections. Design of bolted joints subject to cutting forces. Fatigue design.
3. Welded joints
Concepts and Nomenclature. Types of joints. Types of efforts. Static dimensioning of welded joints according to the criteria: equal resistance and allowable stresses. Sizing of welded joints according to the standards: ISO, Portuguese Regulation and the International Welding Institute.
4. Springs
Concepts and Nomenclature. Most common types of springs: helical, leaf, disc, conical, volute and torsion springs. Stresses and strains in tension and compression helical springs. Design and selection criteria. Mechanical properties of materials usually used in the construction of springs. Springs association. Theoretical analysis of the fatigue phenomenon in springs.
Curricular Unit Teachers
Internship(s)
NAO
Bibliography
FERREIRA, J. A. M., BORREGO, L. P., (2023). Fadiga de Materiais, Textos Pedagógicos, ISEC.
BRANCO, C. M., FERREIRA, J. M., DA COSTA , J. M., RIBEIRO, A. S. (2005). Projecto de Órgãos de Máquinas,
Fundação Calouste Gulbenkian.
SHIGLEY, J. E. (1986). Mechanical Engineering Design – First Metric Edition, McGraw-Hill Book Company.
NIEMAN, G. (1993). Elementos de Máquinas, Editora Edgard Blucher Ltda, vol I, II e III.