Ing Ind - Inf (Mag.)(ord. 270) - BV (483) MECHANICAL ENGINEERING - INGEGNERIA MECCANICA
098506 - ADVANCED DESIGN OF MACHINE ELEMENTS
095119 - ADVANCED DESIGN OF MACHINE ELEMENTS
Mechanical power transmissions play a key role in several application fields, like transportation, energy, both from conventional and renewvable sources, industry, marine. Some typical examples, like helicopter MainGearBoxes (MGB), car and industrial vehicles gearboxes, wind turbine gearboxes or geared turbofan planetary gearboxes, demonstrate the relevance of the transmission in obtaining high performances and in maximizing efficiency, both for the single components and for the whole systems.
The design of a modern transmission requires the capability of applying the most advanced design methods, with respect to structural strength, durability, efficiency and NVH (noise, vibration, harshenss), but it is also foundamental a pre-design, aimed at the proper definition of the layout, with a correct selection and application of the machine elements involved, including a preliminary definition of the proportions, of the tolerances and of the constructive details.
Starting from a review and application of the basic design rules, the course of Advanced Design of Machine Elements is aimed at providing to the students the most recent advances in the field of design of mechanical components like shafts, gears, bearings, bolted connections and couplings.
Risultati di apprendimento attesi
The students will possess the knowledge of the most recent advances in the field of the design of machine elements, taking into account the new theoretical developmnets, tools and requirements from the application (knowledge and understanding).
Thanks to the exercises on gear transmissions, the students will improve the skills necessary for practical design application (applying knowledge) and for the definition of the most appropriate solutions for the fullfillment of detailed and specific requirements (understanding; making judgements).
From the point of view of the organisation, the course is scheduled with four main block of two days each. The first two blocks, held in Milano Bovisa, will be focused on lectures concerning theoretical aspects and on an introduction to the application exercises. A third block, in Milano Bovisa, will deal with the application exercises. The fourth block instead is held in Garching (D), at the TUM (Technical University of Munich), and includes lectures, exercises, a tour of the laboratories of FZG (Gear Research Center) and a Techical Visit of a German Company in Munich.
The topics of the theoretical lectures are the following:
Introduction to the design of machine elements and review of the methods for the assessment of static and fatigue strength. Failures modes, pre-design, assessment, loads and stresses. Static and fatigue assessment.
Sliding-Rolling contact. Hertzian stresses, EHD lubricated contact, Strength, pitting and micropitting. Other failure modes (scuffing, wear). Lubrication and
Rolling Element Bearings. Types of bearings, requirements, selection of bearings, static assessment, fatigue life calculation, speed, mounting solutions, power losses, friction. Lubrication and lubricants.
Mechanichal Power Transmissions. Types of transmissions. Gearboxes, differentials, clutches, belt and chain drives.
Gears. Geometry and kinematics of gears. Gear teeth data. Failure mode of gears. Pitting, Bending, Micropitting, Scuffing, Wear, Calculation methods for the different failures. Standards. Manufacturing of gears. Efficiency. NVH (noise Vibration Harshness).
Shafts, Shaft-Hub Connection and Shaft-Shaft Connection. Shafts. Design and assessment of shafts. Different principles and solutions for shaft-hub connections: friction, geometrical fits, locking elements. Couplings.
Bolted Connections. Screws, nuts, bolts. Loads in bolted connections: joint diagram. Compliance of the joint components. Tightening. Stresses. Assesment: static and fatigue.
Two application exercises will be devoted to the design of the assemblies and to the calculation respectively of a single stage and a multistage gearbox, starting from a functional layout including the main requirements to fulfill. A third exercise will consist on the design of a gear by means of the software in use at the Gear Research Center (FZG) of the TUM.
Real samples of gearbox assemblies and of the machine elements involved will be presented to the students in order to address the design of their own solutions.
In the application exercises the professor will be supported by assistants, both from TUM and POLIMI, in a number depending on the number of students enrolled. Additional weekly meetings can be arranged with italian assistents in the official timetable of the course, in order to discuss the progress of the application exercises.
A detailed schedule of the course, with all the dates defined, will be provided to the students enrolled in advance through "BeeP" and will also be presented at the first lecture of the official timetable published on the website of Polimi.
The course assumes that the students are familiar with technical drawing and its rulesm, with the basics of machine elements and machine design. In particular the students should already know the theory of beams, the calculation of the stresses and the methods for the static and fatigue assessment of machine elements subjected to monoaxial and multiaxial states of stress.
Modalità di valutazione
The application exercises developped by the students, with the support and with the review of the professors and assistants, are compulsory and must by submitted with a deadline that will be agreed during the course. They will be evaluated and will contribute in a relevant way to the definition of the final mark, together with a written exam. The evalution of the application exercises assesses the capabilities of the students of applying knowledge, understanding and making judgements.
The written exam consists of two parts: a first part, with theoretical and application questions, and a second part, in which the students are request to draw a simple assembly. The written exam will therefore assess the theoretical knowledge and will contribute to the assessment of the capability of understanding and making judgements.
G. Niemann, H. Winter, B.R. Hoehn, Manuale degli Organi Delle Macchine, Editore: Tecniche Nuove Note:
Versione Italiana del testo in lingua tedesco in uso presso la TUM
Slides of the course in english available on "Beep"
Tipo Forma Didattica
Ore di attività svolte in aula
Ore di studio autonome
Laboratorio Di Progetto
Informazioni in lingua inglese a supporto dell'internazionalizzazione
Insegnamento erogato in lingua
Disponibilità di materiale didattico/slides in lingua inglese
Disponibilità di libri di testo/bibliografia in lingua inglese
Possibilità di sostenere l'esame in lingua inglese
Disponibilità di supporto didattico in lingua inglese