B001397 - MACHINE DESIGN

Italian

Italian

The course can be considered as divided into two parts. The first one covers the fundamentals of Machine Construction and delves into some of the topics already covered in the course of Strenght of Materials. The concept of fatigue design is introduced and specific applications are examined. The second part concerns the machine elements that are treated from a functional and structural point of view.

The course is divided in two main parts. In the first one the fundaments of Machine Design are presented. These are topics which usually are not treated in the courses of strength of materials but are of special interest for a mechanical engineer. The second part of the course analyses the strength of the Machine elements and their functionalities

1) G. Nerli M. Pierini, Costruzione di Macchine, 2015, Ed. Esculapio, ISBN: 9788874888542
2) G. Nerli, M. Pierini, Costruzione di Macchine: Applicazioni, 2008, Firenze University Press, Firenze; ISBN: 978-88-8453-749-2 (paper version); 978-88-8453-699-0 (electronic version).
3) R.Capitani, M.Carfagni, G.Nerli - Esercizi di Costruzione di macchine. Ed. Levrotto & Bella - Torino 1992

I lucidi del corso sono scaricabili seguendo le indicazioni fornite dal docente all'inizio del corso.

1) G. Nerli, M. Pierini, Costruzione di Macchine, Editrice Esculapio, ISBN: 9788874888542, DOI: 10.15651/978-88-748-8854-2.
2) G. Nerli, M. Pierini, Costruzione di Macchine: Applicazioni, 2008, Firenze University Press, Firenze; ISBN: 978-88-8453-749-2 (paper version); 978-88-8453-699-0 (electronic version).
3) R.Capitani, M.Carfagni, G.Nerli - Esercizi di Costruzione di macchine. Ed. Levrotto & Bella - Torino 1992

The slides used during the lectures are available for download following the indications provided by the teacher at the beginning of the course.

Additional textbooks:
R.C.Juvinall, K.M.Marshek - Machine Component Design - John Wiley & Sons.
R.G.Budynas, J.K.Nisbett - Shigley's Mechanical Engineering Design - McGraw-Hill.
A.De Paulis, E.Manfredi - Costruzione di macchine - Pearson. ISBN 978-88-7192-783-1.

To provide the knowledge necessary to design and verify the mechanical elements and assemblies, with particular reference to the resolution of the functional and structural problems.
Applying knowledge and understanding related to the most appropriate methods of analysis, modelling, verification and experimentation to design, analyze and test machines and plants. This includes: the interpretation and drafting of mechanical parts and machines (also using dedicated CAD systems); the sizing and the functional and structural verification of components and mechanical groups subjected to static and fatigue stress; the functional setting of the design of a mechanical system, applying the principles of kinematics and static principles; analysis of the characteristics of metallic and polymeric materials for the production; the choice of the best production process aimed at the creation of mechanical components; analysis and design of production systems including the study of reliability, safety and economic and environmental sustainability. Applying knowledge and understanding problems related to identifying, formulating and solving industrial and specifically mechanical engineering problems, defining the specifications, technical, but also social, health and safety, environmental and commercial constraints, and resolving them using established methods, thus leading to engineering projects adapted to the level of knowledge and understanding developed. Projects may concern products, devices, machines, energy systems, automatic systems. Applying knowledge and understanding problems related to the choice and subsequent use of appropriate tools and methods - such as software tools for three-dimensional modeling, simulation (structural and fluid dynamics) and management of technical information – for the design and production of components and machines.Applying knowledge and understanding problems related to multidisciplinary engineering, taking into account the constraints also of a non-technical nature, and working in collaboration with other engineers or other professional skills typically present in manufacturing companies.Systematic knowledge and understanding of the key aspects of mechanical design of industrial engineering and its methods. In particular: understanding of which are the most suitable methods in order to define a product and its characteristics; knowledge of the technology of the materials that can be used, of the mechanical study of parts and assemblies, their dimensioning, their static and dynamic behaviour and interactions between components. The technologies for their production and their graphic representation are also areas of knowledge and understanding.Knowledge and understanding of the wider multidisciplinary context of engineering with a particular focus on problem solving, which starts from the problem to identify causes and possible measures (typically multidisciplinary) to tackle them.Knowledge and understanding of information technology including the role they play in supporting design. Understanding the organization of information in databases and computer design to support processes.

Provide the necessary knowledge to perform the design and verification of the elements and mechanical groups, with particular reference to the resolution of functional and structural problems.
Provide systematic knowledge of key aspects of mechanical design, industrial engineering and related methods; for the latter, the understanding of which ones are most suitable for the purpose of defining a product and its characteristics. The technology of usable materials, the mechanical study of parts and assemblies, their sizing, the study of their static and dynamic behavior and the interactions between components, the technologies for their production, their graphic representation are the areas of knowledge and understanding .
The ability to choose and apply appropriate analytical, modeling, verification and experimentation methods to design, analyze and test machines and plants including: the interpretation and realization of detailed and total drawings, even with the use of software systems; the sizing and functional and structural verification of statically and fatigue components and mechanical units; the functional setting of the design of a mechanical system, applying the principles of kinematics, kinetostatics, static and dynamics; the analysis of the characteristics of metallic and polymeric materials for the construction of components, taking into account the conditions of use; the ability to choose the best production process for the realization of mechanical components; the analysis and design of production systems including the reliability, safety and economic and environmental sustainability study.

Mechanical drawings, strength of materials, applied mechanics, mechanical technologies.

Mechanical drawings, Strength of materials, Applied mechanics, Mechanical technologies.

Classroom lectures and exercises

Classroom lectures and exercises

Online exam booking page:
http://sol.unifi.it/prenot/prenot

Examination is divided into a written and an oral test.The written test consists in drawing up a constructive sketch of a simple mechanical system. The student must be able to implement a constructive solution. The oral test includes: a theoretical question; an analysis of the design of a mechanical group, with an evaluation of the functioning and the distinction of one or more elements of the machines included in the group; the design of an element of the machines. The student must demonstrate that he or she has acquired sufficient knowledge of the main topics dealt with in the course.

Written and oral exam.
The written test consists in the constructive design of a machine or a mechanical group. The oral exam includes: a theory question; the analysis of the design of a mechanical group, with evaluation of the functioning and the distinction of one or more elements of the machines included in the group; the design of an element of the machines.
The student must be able to carry out a functioning and "mountable" construction solution to pass the written exam. As regards the oral examination, the student must have acquired sufficient knowledge of the main topics covered in the course.

- Mechanical design and related methodologies.- Resistance and stiffness testing considerations.- Materials used in mechanical engineering.- Design and verification under static load conditions.- Design and verification under fatigue load conditions.Some structural topics of interest for the mechanical constructions:- Hertzian contacts,- pressure components, - rotating elements.Machine elements: - bolted connections, - welded connections, - connections for forcing, - glues,- design and testing of pins, axles and shafts,- detachable connections: keys, tabs, plugs, grooves,- screw connections,- manoeuvring screws,- plain shaft bearings,- rolling bearings,- springs: torsion bar, coil spring, bending springs, - sprockets: cylindrical and conical wheels with straight and helical teeth, pair of worm gears and helical wheels,- flat, round, trapezoidal and poly-v belts, toothed belts,- transmission chains.

Mechanical design and mechanical design process
- Stiffness and strength considerations
- Materials for mechanicals parts
- Design for static strength
- Design for fatigue strength
Topics of interest for machine design:
- Hertz contacts
- pressure vessel
- rotating parts
Machine elements:
- bolted joints
- welded joints
- shrink fits joints
- bonded joints
- design of axle and shaft
- keys and pins
- screws connections
- power screws
- journal bearings
- rolling contact bearings
- springs
- spur, helical, worm and bevel gears
- belts and roller chain