The aim of the course is to provide the student with knowledge and skills in mechanical dsign. In detail: Knowledge [A] knowledge of the main types of failure of the machine components with reference to the properties of the materials [B] understanding of the principles of mechanical design and specific methodologies for the design of important elements of the machines and Joints , using the main technical standards [C] understanding of machine component drawings, with the interpretation of the function of the components and of the construction details Skills [D] interpretation and understanding of mechanical drawings [E] understanding the assembly and assembly criteria for mechanical components [F] perform the design and verification of mechanical elements and jonts [G] draw machine components and mechanical systems in a simplified form

- Knowledge of the principles of technical drawing in accordance with ISO standards. - Ability to perform kinematic analysis of simple mechanisms. - Ability to perform stress calculation in beam elements. - Knowledge of the behavior of metallic materials under static load (parameters obtained from the tensile test). - Basic knowledge of the behavior of metallic materials under fatiguing loads in laboratory conditions, uniaxial stress state. - Ability to perform static verification and fatigue verification calculations on simple elements such as beams or specimens. - Knowledge of the main heat treatments in metallic materials.

The course aims to provide the minimum knowledge for the design, verification, interpretation of the main components of a machine. The course is a development of the discipline of Fundamentals of Structural Mechanics and it paves the way towards the applications to the mechanical design. The course includes the general aspects of the resistance of mechanical components subjected to static and dynamic stresses (fatigue) and the calculation procedures of some of the main components of the machines and joints. Course topics (summary) - Failure due to fatigue. Basic concepts, diagrams of engineering use, effects that influence fatigue life, notches, component safety. Multiaxial stresses and durability. - Axes and shafts. Stress state, static and fatigue calculation and verification procedures. - Gears. Basic principles of meshing, tooth geometry and involute flank design, calculation of the forces between the meshing teeth for spur and helical gears, calculation against failure for fatigue and wear, according to techical Standards. - Stress state due to contact loads: basic concept of Hertz theory and application examples. - Axis-symmetric solids. Stress state in thin walled structures and in thick walled vessels. - Hub-to-shaft fitting. Fitting by interference, under ISO rules within dimensional tolerancing. Tapered keys, keys, pins, parallel key splines. - Rolling bearings. Geometry, life and selection from the catalogue of commercial products. Assemblies, rules for assembly and examples.. - Connections shaft–to–shaft. Couplings between two shafts and preliminary remarks about their design. Clutches, geometry, design and behavior - Threaded connections. Description, interference diagram, loads due to the clamping, materials. Drawing of threads. Screws and geometries. Load distribution upon the threaded joint (screw and member). Unlocking and uncertainties. Minimum loading condition. Shear effect on screws. Static and fatigue strength. - Welded joints. Welding technology. Defects in welded joints. Butt and fillet welds. EuroCode rules to predict the static and the fatigue strength. Variable amplitude loading conditions and Miner’s rule. - Springs. Typologies of springs and drawing. Examples with related application. Characteristic curve of spring behavior and effectiveness. Springs in series and in parallel. Torsion bars, helical springs, static and fatigue design. Leaf springs and simplified formulas for design..

The student, at the end of the course, will acquire the knowledge of the main machine components, as well as the ability to carry out preliminary design and verification according to the main technical standards. The student is expected to acquire well-defined skills such as: 1. Carry out preliminary verification and design calculations of the main machine elements, with the use of tables, diagrams and formulas from technical Standard; 2. Read and interpret the drawings of mechanical assemblies of medium complexity and understand functions in working condition; 3. Understand the assembly criteria of mechanical components and be able to do manual sketches to illustrate their operation. The ability to solve the real problems that arise in professional life is acquired by developing the ability to combine theory with its practical application. The exercises proposed in the course offer simple but real cases of application aimed at leading students to a complete understanding of the aspects of theory, by employing them in example of professional problems. The exercises allow students to acquire sensitivity towards the orders of magnitude of the numerical values involved. In this sense, it is highly recommended, during the exercises and the written exam, to make use of graphic solutions and carry out the dimensional analysis of the results obtained. A more specific orientation towards the profession is offered by the development of a technical report. This is about the design / verification of a machine component, to be designed according to the requirements of the technical standards. With this in mind, it is clear that the offer provided by the proposed cycle of lessons and exercises is effective at the educational level only if each student participates continuously and actively. Organization of the practice hours. The students are divided during the first week into teams of 2 or 3 students, each student will carry out the exercises collaborating with the other members of his/her team. During the practice hours, exercises will be partly carried out by the teacher, partly carried out independently in the classroom by the students with their own team. Some of these practice hours will be dedicated to explain the working procedure for the technical report, relating to the design / verification of the assigned machine part. Each student will then carry out as homework with his/her own team the technical report. Each team shall produce ONLY one technical report,. The technical report must be presented by the student, during the ORAL exam. We therefore recommend that each student have a copy of technical report of his/her team.

Main study material Slides of classes, available on the course website. The slides were prepared by the teachers in the form of self-explanatory presentations of the course contents. Textbooks (not mandatory) -R. Budynas, J. Nisbett, Shigley – Progetto e costruzione di macchine, McGraw Hill, Edizione Italiana (II),2008 e seguenti -A. De Paulis, P. Forte, F. Frendo, E. Manfredi, "Costruzione di macchine", Pearson, Italia, 2019. -M. Rossetto, Introduzione alla fatica dei materiali e dei componenti, Levrotto & Bella, Torino, 2000 -L. Goglio Resistenza dei Materiali e dei Collegamenti, Levrotto & Bella, Torino, 2006 Additional references (not mandatory) R.C. Juvinall, K.M. Marshek, Fundamentals of machine component design, John Wiley & Sons, 2006 -G. Niemann, H. Winter, B. Höhn, Manuale degli organi delle macchine, Tecniche Nuove, Milano, 2006 -A. Strozzi, Lezioni di Costruzione di Macchine, Pitagora, Bologna, 1998 -S. Suresh, Fatigue of materials, Cambridge University Press, Cambridge, 1998 -R. Giovannozzi, Costruzione di Macchine, voll. 1 e 2, Patron, Bologna, 1980 (storico) -U. Pighini, Elementi Costruttivi delle Macchine, Edizioni Scientifiche Associate, Roma, 1980 (storico) -J.A.Collins, Failure of Materials in Mechanical Design, John Wiley & Sons, 1980 (storico)

Lecture slides; Exercise with solutions ; Video lectures (previous years);

Exam: Written test; Compulsory oral exam; Group graphic design project;

Each student is required to develop the following skills: 1. To be able to perform some preliminary numerical investigations about the design and verification of typical machine elements, by resorting to tables, diagrams and formulas proposed by technical standards and directives; 2. To be able to read and understand basic drawings of mechanical assemblies, exhibiting average complexity, to detect the functions and the behavior of the devices being there depicted; 3. To be able to use the Solidworks tool by introducing all the tolerances required by Standards and useful for manufacturing. The final mark is composed of the evaluation of the two parts ELEMENTS OF MACHINE DESIGN and ELEMENTS OF MACHINE DRAWINGS. Evaluation of the part ELEMENTS OF MACHINE DESIGN The exam consists of two tests : - a written test (score A) - an oral test allowing the student discussing the project developed during the tutorials (score C) Each student must attend both those tests (written and oral) according to the official schedule published online. The oral test is usually straight after the written test. To access to the oral test each student must obtain a score of at least 18/30 in the written test. It is required that both tests are performed in the same exam session (meaning same “appello”). It is compulsory that each student brings at both the written and oral test an identity card and/or the University card with a clear picture in order to be allow verifying his/her identity. During the written test it is compulsory to switch off all the cell-phones and any other device able to be connected to the network. Every communication among students in class, or by portable, as well as the use of cheat sheets, of books or notes will be considered a major misconduct. In that case the student will be asked to deliver the examination sheets and to leave the room. At the oral exam each student must provide his/her technical report, complete in all its sections of calculations and drawings. In case of either missing or incomplete technical report the student will be rejected and will perform again both the tests, during another session. Written test The written test consists in: - 3 questions each one dealing with a topic of ELEMENTS OF MACHINE DESIGN explained during the classes; the answer must be concise, formulas and graphs are required, books or notes are not allowed; - 3 exercises to be solved in numerical form, the exercises are similar to those proposed during the tutorials. The written test is thought to verify the student understanding of topics explained during both lectures and tutorials. It verifies the achievement of a good level in skills 1 and 2. The sheets for the written test are provided to students at the beginning of test. Each student must have all the required tools to write and to draw. At the end of test each student will deliver all the sheets received. The written test is about 2h long, each student can withdraw within 15 minutes since the beginning. Each question and each exercise are evaluated with a score spanning from 0 to 5 points, giving a maximum of 30 points for all of questions and exercises composing the test. This score is herein called Score A. Oral test: The oral test is scheduled usually few days after the written test. 1) Each student can read first his/her written test, being informed by the teaching staff about the grading. During this action the student cannot communicate with other colleagues nor compare answers and results. In case of communication the score could be decreased. However the score of the written test (already decided) could be modified and even slightly increased, in case that the student could demonstrate that during the correction his/her interpretation in some answers or exercise was partially misunderstood. 2) As a second step of the test, each student will be required to defend his/her technical report. Therefore each student must come to the oral test with a copy of the technical report developed in team at home and during the tutorials. That defence will be scored from –2 to +2 points, depending on how the student answers to the questions during the oral test and on the quality and the completeness of the report, which must include all the required drawings. If the student will be unable to show and discuss the technical report during the oral test, the whole exam will be null and will be completely repeated (written and oral tests). This score spanning from –2 to +2 points will be called Score C. Evaluation of the part ELEMENTS OF MACHINE DRAWINGS This evaluation will be based on the judgement of all of drawings performed during the course (one full copy of drawings for each working team of students is required), this evaluation will be done during the classes. The knowledge of theoretical topics explained during the classes will be evaluated during three tests assigned to the students in three different days during the semester. Evaluation of both the tests and of drawings will lead to a final score up to a maximum of 30/30. This score will be herein called Score B. The score B will be computed as follows: Score_B = Average Score of the tests (out of 30) * 26/30 + Score for the Drawings (out of 4) If the student does not pass the tests, this evaluation will require an additional oral test, being performed at the dates officially scheduled. It deals with all the topics proposed during the classes and the tutorials of ELEMENT OF MACHINE DRAWINGS. Final score of the integrated exam The score of the part ELEMENTS OF MACHINE DESIGN will be averaged with the score of the part ELEMENTS OF MACHINE DRAWINGS according to credits assigned to each part as follows : Final score = 2/3*(Score A+Score C) + 1/3*Score B If the final score will be higher than 30/30, “laude” (lode) could be assigned upon judgment of the evaluation committee eventually by asking the student one or two questions, about all the topics explained during the classes.

In addition to the message sent by the online system, students with disabilities or Specific Learning Disorders (SLD) are invited to directly inform the professor in charge of the course about the special arrangements for the exam that have been agreed with the Special Needs Unit. The professor has to be informed at least one week before the beginning of the examination session in order to provide students with the most suitable arrangements for each specific type of exam.