B010668 - MECHANICAL BEHAVIOUR OF MATERIALS

Italian

In the course the main notions concerning the structure of metals and their alloys are presented, with particular reference to the mechanical properties

F.Pratesi: Microstruttura e proprietà meccaniche dei materiali. Aracne. ISBN 978-88-548-2163-7
N.E.Dowling: Mechanical Behavior of Materials. Prentice Hall
Ashby M.F.-Materials Selection in Mechanical Design (4ed). Butterworth-Heinemann
G.E.Dieter - Mechanical Metallurgy. McGraw-Hill
L.Vergani: Meccanica dei materiali. McGraw-Hill

The course aims at giving the fundamental knowledge for selecting metallic materials in mechanical applications, in order to guarantee the best performance. With this purpose, the relations between mechanical properties and microstructural characteristics are described. The course has the following objectives:
- To provide the knowledge and understanding of materials and their behaviour in the various loading conditions found in design practice. Methods for characterising material behavior (cc5).
- To apply the knowledge and understanding related to the analysis and optimization of mechanical devices and systems, as well as to their innovation also through the development and improvement of design methods, constantly confronting with the rapid evolution of mechanical engineering (ca3)

Knowledge of the sizing methods of structures and components subjected to static and fatigue stresses. Knowledge of the phenomenon of fatigue in the elastic field. Knowledge of the main properties of the materials.
Knowledge of the basics concepts concerning applied mechanics, structural strength of materials and processing technologies.

Classroom lectures and exercises

The evaluation of the student includes two written tests in progress / in itinere or alternatively an oral exam at the end of the course. The student must show the ability to select, characterize and understand the behavior of the main materials used in mechanical engineering. To pass the test, the student must prove the achievement of the objectives “cc5” and “ca2”.

Material selection in mechanical design
Role of material in design, material property charts, material performance indices and selection procedure

Crystal structures
Metallic crystal systems, crystallographic points, directions and planes, close-packed crystal structures, point defects, plastic strain and slip systems, edge and screw dislocations, Burgers vector, motion of dislocation, energy and stress fields, dislocation multiplication, twinning, grain boundaries

Metal alloys
Solid solutions, phase diagrams, work hardening, strengthening of metals by solid solution, particle hardening, strain aging, oxide dispersion

Creep
Phenomenology, presentation of engineering data, deformation mechanisms, constitutive equations, models of linear viscoelasticity, relaxation, time-temperature parameters

Low cycle fatigue
Cyclic behaviour, Manson-Coffin and Basquin relations, high temperature low cycle fatigue, life prediction methods, creep-fatigue interaction, strainrange partitioning