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MECHANICS OF MACHINES (B)

Academic year and teacher
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Versione italiana
Academic year
2022/2023
Teacher
GIORGIO DALPIAZ
Credits
6
Didactic period
Secondo Semestre
SSD
ING-IND/13

Training objectives

The module is aimed at acquiring knowledge and skills about the concepts and the methods for the functional synthesis of machines; in particular it deals with lubrication, gears and gear trains, as well as vibrations of single degree of freedom systems (vibration isolation).
The course takes into account both the theoretical and the applicative point of view.
The skills are acquired through numerical exercises about component design procedures.

Prerequisites

Courses of Mathematics, Physics and Theoretical Mechanics.

Course programme

The course lasts 60 hours, including lessons and exercises.

The course topics are the following.
TRIBOLOGY AND LUBRICATION (25 hours): Friction and wear in sliding and rolling contacts. Lubricant viscosity and properties. Elementary theory of hydrodynamic lubrication; technical applications. Journal bearings: theory and design (use of Raimondi-Boyd diagrams). Hydrostatic lubrication; technical applications. Performances and applications of bearings.
GEARS (25 hours): Spur gears: properties of the involute, velocity ratio, static analysis, manufacturing processes, contact ratio and interference, dimension standards, non-standard gear teeth, gear measurements. Helical gears. Bevel gears. Worm gears.
GEAR TRAINS (5 hours): Ordinary gear trains. Planetary gear trains. Differential gear systems. Torque relationships in gear systems.
VIBRATIONS OF SINGLE DEGREE OF FREEDOM SYSTEMS (5 hours): Free vibrations. Forced vibrations. Vibration isolation.

Didactic methods

Theoretical and practical lessons; the practical lessons concern numerical exercises on component design and selection.

Learning assessment procedures

Examination of Part B: written/oral. It consists in three questions: two questions are theoretical and methodological, mainly aimed at assessing the knowledge; one question is a numerical exercise, mainly aimed at checking skills in the procedures for dimensioning and selection of components. The questions are carried out in writing and are immediately corrected and discussed orally. The rating assigned to each question refers to both written and oral performances. To pass the exam, it is necessary to be sufficient in each of the three questions and achieve a minimum final grade of 18/30, as the average of the marks on the three questions.
To take the exam it is necessary to present the assigned exercises to be carried out in writing, which will be checked and discussed.
The exams of Part A and Part B must be taken separately, in separate sessions, without any prerequisites for one with respect to the other (Part B can be taken first with respect to A or vice versa). Once one of the two modules has been passed, it always remains valid, independently of the other.
The final grade of the integrated course of Mechanics of Machines A+B is the arithmetic average of the marks obtained in the exams of Parts A and B.

Reference texts

Reference text:
- Funaioli, A. Maggiore, U. Meneghetti, Lezioni di Meccanica applicata alle macchine. Prima parte: Fondamenti di meccanica delle macchine, Patron, Bologna, ISBN 88-555-2829-7, 2005 [Vol. I].
- Funaioli, A. Maggiore, U. Meneghetti, Lezioni di Meccanica Applicata alle Macchine. Seconda parte: Elementi di Meccanica degli Azionamenti, Patron, Bologna, ISBN 978-88-555-2948-8, 2007 [Vol. II].

In addition, supplementary didactic material in pdf format are made available in the Classroom of the course.

Other complementary texts:
- Callegari, M., Fanghella P., Pellicano F., “Meccanica applicata alle macchine”, seconda ed. 2017, Città Studi Edizioni.
- Paolo Righettini, Guido Ruggieri, "Ruote dentate con spostamento del profilo", ISBN: 88 386 6135-9, aprile 2003, McGraw-Hill Companies, S.r.l., Milano.
- Ghigliazza R., Galletti C.U., "Meccanica applicata alle macchine", UTET, Torino, 1986.
- Waldrom K.J., Kinzel G.L., "Kinematics, Dynamics, and Design of Machinery", John-Wiley & Sons, 1999.
- Uicker, J.J., Pennock, G.R., Shigley, J.E., "Theory of Machines and Mechanisms", Oxford University Press, terza edizione 2003, ISBN 0 19 515598 X.
- Doughty, S., "Mechanics of Machines", John-Wiley & Sons, 1988.