Mechanization of agricultural machineries represents the key to increase productivity in farming operations. The design and modelling of mechanical systems and the dimensioning and verification of their components represent a key piece of knowledge for the Agritech Engineer. Therefore, the objective of this course is: - to provide the students with the basic modeling techniques to describe the kinematics, statics, and dynamics of rigid bodies - to provide the students with the necessary knowledge about structural analysis and dimensioning of mechanical components under static and cyclic loads - to describe the main characteristics of a mechanical power transmission system and of its components, with specific focus on agricultural machines The course links the description of the physics underlying the behavior of mechanical drives and their components to the methods instrumental in solving engineering problems such to enable the students to identify the main characteristics of an agricultural machine and to properly address problems relevant to this system.

The course aims at developing the ability of the student to identify both the functional and structural problems relevant to rigid bodies mechanics and mechanical drives, to address and solve them with a scientifically correct approach. At the end of this course, the student will have the knowledge of: - the kinematic characteristics of a mechanical system - the dynamic characteristics of a mechanical system - the general layout of a mechanical power transmission system and of the main kind of components used in such a system - the operating principle of the devices used for transmitting motion - the energy dissipation phenomena occurring during the motion transmission - the strength parameters of materials and components - the methods for describing the stress and strain state in the elastic linear region - the static failure criteria - the basic principles of fatigue phenomenon in structure subjected to time-varying uniaxial loading conditions - the fatigue verification techniques for time-varying loading conditions As a consequence, the student will be able to: - develop functional models of real planar mechanisms, to determine their kinematic characteristics by graphically solving vector equations (triangle of velocities, polygon of accelerations) - identify the free-body-diagram of a mechanical system or of its parts, to determine the static or dynamic balance condition as a function of the external loading - identify the main characteristics of a mechanical power transmission system, evaluating the force/torque exchange - choose the appropriate driving system for a given user - perform the stress analysis of beam-like structures under known load conditions - perform static and fatigue verifications - design and verify some of the major elements of machines and joints (axes and shafts, axisymmetric solids, hub-shaft connections, bearings, springs, threaded fasteners and bolts, welded joints) The ability to solve real problems that an engineer must face in his professional life is achieved by developing the ability to apply theoretical models to practical applications. Thus, exercises propose simple but realistic problems whose objective is to lead the student to a full comprehension of the theoretical basis to use it in everyday professional life.

Prerequisite for attending the course is: - the knowledge of the concepts of differentiation and integration, study of function, trigonometry and vector analysis, matrix algebra, solution of eigenvalue/eigenvectors problems, and some basics of material sciences (material classes and properties) - The ability to understand mechanical drawings

The course covers the fundamentals of applied mechanics and machine design and consists in front lectures (52 h) and applied classes (28 h). • Classification of agriculture machinery • Tractor architecture • Kinematics of mechanical systems: planar kinematics of rigid bodies; constraints and degrees of freedom; position, velocity, and acceleration determination; outline of relative motion; examples of mechanisms in agriculture machines • Statics: - forces and torques; free-body-diagram; examples - basics of internal stress calculation and safety factors • Dynamics of mechanical systems: - Newton’s laws of dynamics; examples - Work and energy, power, and efficiency • Friction: - static and dynamic friction, rolling friction; examples - basics of tire/track soil interaction in agricultural machines • Powertrain components: - spur gears; gearing design procedures and fatigue verification according to AGMA standards; gearboxes; epicyclic gearing; differential; examples - shaft and spindles: basics of mechanical fatigue at high number of cycles (HCF) examples - bearings: types, catalogue selection, endurance evaluation, mounting solutions; examples - hub-shaft fitting: stress field in axisymmetric solids, interference assembly, use of ISO tolerancing tables for stress state calculation, examples. - shaft joints: main connection methods, permanent and moveable (keys, splines, pins, etc.) - Cardan joint - clutch - threaded connections: description and standards, static and fatigue verifications; examples - springs: types of springs, applications, springs in series and in parallel, static and fatigue verification; examples • Transient motion in mechanical systems: direct motor-user coupling; motor-user coupling through a gearbox; coupling by means of clutch; periodic steady machines; flywheel; examples • Brief overview on service robotics for precision agriculture Possible online course delivery will not cause any modifications of the course contents.

The course (8 credits: 52 lecture hours, 28 tutorial hours) is organized as follows: - 26 lecture hours to cover the fundamentals of applied mechanics + 14 tutorial hours on the specific topics - 26 lecture hours to cover the fundamentals of machine design + 14 tutorial hours on the specific topics Theoretical lectures are supported by examples and applications. During the tutorial class hours, the students are provided by materials and frames of solution. The teacher will assist students during the tutorial class hours, supporting them in their learning progression and clarifying their doubts. Attendance to both lectures and tutorials is strongly recommended, being vital to achieve the expected learning outcomes. Neither intermediate formal checks of the learning process nor reports on projects are programmed. The teachers are available to meet students for consultation; please contact them by e-mail. Possible online course delivery will not cause any modifications of the course organization.

Main study references: • Budynas, R., Nisbett, J., Shigley’s Mechanical Engineering Design, 9th Edition in SI units, McGraw Hill, 2011 • Juvinall, R.C., Marshek, K.M., Fundamentals of machine component design, 5th Edition, Wiley, 2011 • Meriam, J. L., Kraige L. G., Engineering Mechanics Dynamics, 7th Edition, Wiley, 2013. • Childs, P.R.N., Mechanical Design, 2nd Edition, Elsevier, 2004 (also in eBook format, see library website) • Collins, J.A., Failure of Materials in Mechanical Design, 2nd Edition, Wiley, 1993 • Renius, K. Th., Fundamentals of Tractor design, Springer, 2020 Additional textbooks: • C. Ferraresi, T. Raparelli: "Meccanica applicata", 3a edizione, 2007, CLUT • Somà A., Fondamenti di Meccanica Strutturale, Levrotto & Bella, Torino, 2019. • Rossetto, M., Introduzione alla fatica dei materiali e dei componenti, Levrotto & Bella, Torino, 2000 • Goglio, L., Resistenza dei Materiali e dei Collegamenti, Levrotto & Bella, Torino, 2006 • Strozzi, R., Lezioni di Costruzione di Macchine, Pitagora, Bologna, 1998 • Furgiuele, F., Sgambiterra, E., Esercizi di elementi costruttivi delle macchine, Pitagora, Bologna, 2022.

Slides;

Modalità di esame: Prova scritta (in aula);

Exam: Written test;

... Achieved learning outcomes will be assessed by means of a final written exam. This is based on an analytical assessment of student achievement of the “expected learning outcomes” described above. The final written exam (duration: 2 hours) consists of questions and exercises on the content of the course and is made up of two parts, each ranked from 0 to 30: one part concerns the fundamental of applied mechanics and the other one concerns the fundamentals of machine design. In each part, the students will be asked to solve: - one problem using calculations, so to assess their ability to choose the most suitable mathematical instrument - one more theoretical question. To pass the exam, students must achieve 18 out of 30 for every part. The final grade will be the average of the grades obtained in the two parts. Students that achieved 30 out 30 for both parts, will be evaluated by 30/30 cum laude. The exam is a closed book one. The calculator can be used. A few days after the written test, the exam results are available and the students are summoned for a review of the written output, during which examiners inform the student on grading criteria, and receive any student appeal supported by appropriate explanations. Further details on exam rules are given on the official course website.

Gli studenti e le studentesse con disabilità o con Disturbi Specifici di Apprendimento (DSA), oltre alla segnalazione tramite procedura informatizzata, sono invitati a comunicare anche direttamente al/la docente titolare dell'insegnamento, con un preavviso non inferiore ad una settimana dall'avvio della sessione d'esame, gli strumenti compensativi concordati con l'Unità Special Needs, al fine di permettere al/la docente la declinazione più idonea in riferimento alla specifica tipologia di esame.