Mechanical Engineering

The course is divided in two different parts (3 CFU each), namely “Chemistry of Materials” and “Materials Technology”) that will be administered during the first semester of the third year. Each part will last one month and a half. Topics covered (Non Metallic Materials for Engineering - Part I Chemistry of Materials) FUELS. Introduction to organic chemistry; Aliphatic, cyclic and aromatic hydrocarbons (Paraffins, naphthenes, aromatics and olefins). Petroleum chemistry (Topping) and derivatives. Natural fuels: Gaseous fuels, and liquids (methane, LPG, gasolines, kerosene, gas oil, fuel oil and bio-fuels) Petrochemical processes to modify the yields of the various fractions of fuels (cracking, hydrocracking, Reforming, isomerization). Pollution from fossil fuels. LUBRICANTS. Viscosity. Liquid lubricants: oils and greases; Solid lubricants: graphite and teflon. POLYMERIC MATERIALS. Functional groups in organic chemistry. Halides, alcohols, phenols, ethers and thiols. The carbonyl group: aldehydes and ketones. Carboxylic acids and their derivatives (esters and soaps). Amines and amides (nylon6-6). Carbohydrates (starch and cellulose). Lipids. Amino acids, peptides and proteins. Nature of macromolecules. Replacement, addition and condensation reactions. Radical reactions. Main polymerization reactions. Thermoplastic materials; relations between the chemical structure and their properties and uses of the following plastic materials: polyethylene (HDPE, LDPE LLDPE); PVC; PP (atactic, syndiotactic and isotactic); PB; PMP poly-methylpentene; PVAC; PS; PAN; SAN; ABS; PMMA; PTFE and PCTFE. Tecnopolimers; relations between the chemical structure and their properties and uses of the following materials: Polyamides (Nylon 6-6, 6-9 and 6-10); Aramids (Kevlar and Nomex); Cellulose and its derivatives (Rayon); Polycarbonate (Lexan); Polyesters (PET polietilentereftalato and PBT) and Poliarylates (PAR); polysulfones; polyketones; Policianoacrylates (cyanoacrylic glues)]. Thermosetting polymeric materials [Phenolic resins (ESA hexamethylenetetramine crosslinking) Bakelite; Epoxy resins (crosslinking with diamines); Polyimides. Elastomers; relations between the chemical structure and their properties and uses of the following materials: Natural rubber (vulcanization); Synthetic rubbers SBR (styrenebutadiene) and PIB (polyisobutylene); Nitrile rubbers; Polychloroprene (neoprene); Silicone rubbers. Carbon fibers (PAN and Pitch synthesis, uses). Composite materials. Chemical stability and degradation of polymers and composite materials. CERAMIC MATERIALS. Introduction to crystallography (Bravais lattices); CCC, CFC and EC structure. Miller's notation system of crystallographic planes, and notes on X-diffractometry, Bragg's law and phase identification (CCC and CFC). Solid substitutive solutions and solid interstitial solutions. Crystalline defects (Schottky defect and Frenkel defect). Analysis of crystalline structures (of the ZnS type, fluorite and antifluorite, Al2O3, Peroskite). The crystalline structures of silica and silicates (island, chain and layer). Glasses (unbreakable, tempered glass and crystals). Ceramics based on oxides, nitrides, carbides and borides. Chemical, thermal and mechanical properties and of glasses and ceramics. Chemical stability and degradation of ceramics. NATURAL ORGANIC MATERIALS. The wood. Topics covered (Non Metallic Materials for Engineering - Part II Materials Technology) Polymers - Introduction and key terminology - Polymer synthesis - Polymer cryistallinity and molecular configurations - Classification of polymers: elastomers, thermoplastics and thermosets - Thermal transitions in polymers (crystallization temperature and glass transition temperature) - Mechanical properties of different classes of polymers - Viscoelastic behaviour and related simple mathematical models (Maxwell and Voigt) - Processing of polymers Ceramic materials - Introduction and key terminology - Ceramic crystal structures - Silicate ceramics - Mechanical properties of ceramics and subcritical crack growth - Toughening mechanisms - Fracture statistics of ceramics (Weibull) - Fabrication and processing of ceramics (solid state sintering) Composite materials - Introduction and key terminology - Fibrous materials for polymer and ceramic materials - Micromechanics of continuous and discontinuous lamina - Processing of composite materials based on polymer matrices (autoclave forming, hand lay-up, filament winding, pultrusion)

The materials field represent an interdisciplinary subject, spanning the physics and chemistry of matter, engineering applications and industrial manufacturing processes. Therefore, the students are expected to have a good knowledge of maths (Analisi I) and fundamental sciences including chemistry (Chemistry) and physics (Physics I).

- W.F. Smith “Elementi di Scienza e Tecnologia dei Materiali”, McGraw-Hill ed. - W. D. Callister, D. G. Rethwisch “Materiali per l’Ingegneria Civile ed Industriale”. Edises, 2015 - Lecture notes provided by the instructors

The course is organized on traditional lecture-based classes. Students will be actively engaged by collecting information and asking questions. Numerical exercises will be solved in class in order to make theory more easily learned.

Class attendance is not compulsory, even though it is highly recommended.

The course, being divided in two parts, is based on two different and separate examinations. The final mark is the average of the marks received in the two parts. Each mark needs to be higher than 18/30. Course grading for Non Metallic Materials for Engineering - Materials Technology will involve a final exam, which will be written and quantitative. The final exam will be administered in class according to the schedule available in the platform “Infostud”. The exam will last 90 minutes and will include three open-ended questions on the topics discussed in class, five multiple choice questions and two numerical exercises, which are designed to develop students’ understanding of concepts and facility with skills. Open-ended questions aim at verifying the knowledge of the topics discussed in class. The final mark resulting from the written test is based on the quality and thoroughness of the answers and related reasoning. Overall, the written exam aims at verifying that the students gained knowledge and understanding of the information provided in class, not only from the theoretical point of view, but also with reference to simulated practical cases. The students’ capability of autonomous learning is also tested, e.g., by suggesting additional reference material.

The course is organized on traditional lecture-based classes. Students will be actively engaged by collecting information and asking questions. Numerical exercises will be solved in class in order to make theory more easily learned.