Home | Research projects | Courses and modules | 3. a semester - University of Coimbra, Portugal

Course Overview

Module objectives

The main objective of this course is to prepare the students for their thesis, supplying them with basic concepts of the main failure modes in mechanical engineering and the way how to characterize the mechanical behaviour of a material. This is a fundamental part in the understanding of the tribological behaviour. Therefore, the fundamental knowledge of mechanical behaviour, such as elastic and plastic strains, ductile and brittle failures, fatigue, wear and corrosion, will be presented. In the same line, the main techniques used for the characterization of that behaviour will be introduced. The students should acquire the competences to understanding the described phenomena and to proceed in an autonomous way in the activities of quality control, materials selection and maintenance.

Outline syllabus

• Failure modes in materials – elastic and plastic strains; ductile and brittle failures; failure characterization.
• Fracture - Griffith theory; release rate of energy; stress intensity factor; plastic deformation in the tip of the crack; dependence of toughness on the sample thickness, temperature and kind of material; opening crack displacement; J integral 3. Fatigue – fatigue process; endurance limit; oligocycle fatigue; analysis of cracks propagation; fatigue curves; thresohld and speed parameters in cracks propagation; applications of da/dN-DK curves.
• Creep – classes of creep; importance of creep in components with long life; stress relaxation and recovery; design of materials submitted to creep loading. 5. Corrosion – metallic corrosion; corrosion types; corrosion protection and prevention; specific cases of corrosion (biocorrosion and stress corrosion). 6. Wear –failure modes and their interaction in the wear mechanisms; examples of application
• Techniques for samples preparation – metallography; ion milling; cross section TEM preparation.
• Morphological analysis – profilometry; grain particle distribution; porosity evaluation.
• Corrosion analysis – voltametry; potentiometry; polarigraphy; electrogravimetry.

Monitoring of student progress:

• Laboratorial or field works
• Written examination

Partners

The key academic groups of TRIBOS consortium are leading and world renown in their own field of Tribology and Surface engineering. They are very complementary from point of view of surfaces, lubricants and interfaces, as well as engineering component design. Thus, their involvement in a single programme enables integration of the whole range of tribology sub-areas required for successful application solutions.