03OAIQW

A.A. 2021/22

2021/22

Dynamic design of machines

The aim of the subject is to give the students the basic knowledge needed for the structural dynamic analysis and the dynamic design of machines. Computational methods, and more in detail the numerical methods more common in the design practice will be intorduced. Theoretical aspects needed to obtain the deeper knowledge of the subject required to operate in the present innovative industrial environment are not neglected. The last part of the course is dedicated to the study of the dynamic analysis of rotating machinery, dynamic behaviour of electromagnetic controlled systems.

Dynamic design of machines

This course presents the relevant principles for understanding structural dynamics and its relationship with and design of machines. Topics covered include eigenvalue problems, modal analysis, frequency response and transient response. Discrete systems of complex structures are developed using numerical methods such as finite element or matrix structural analysis. The last part of the course is dedicated to the study of the dynamic analysis of rotating machinery and dynamic behavior of electromagnetic controlled systems. The course work includes computer algebra, computer simulation, and experiments in the laboratory.

Dynamic design of machines

Students are required to learn the basics of the dynamics of vibration and of the analytical and numerical methods commonly used for machine design. Students must learn how to apply this knowledge to the actual dynamic study of machines and their elements, using them in a machine design context. The ability of interpreting in a critical way the results obtained, in particular through numerical methods, is also required. Student must also learn to produce technical documentation of the work done.

Dynamic design of machines

After this course, students will understand how to evaluate the dynamic behavior of mechanical systems. Students will acquire the ability to integrate structure dynamics in a wider spectrum of machine design problems. The ability to critically interpret the results will also be acquired. In addition, students will learn how to produce a technical report to disseminate the work done during the Project activities.

Dynamic design of machines

A good knowledge of the basic concepts of applied mechanics and of the methods of static stress analysis is required. A basic ability in using the relevant computer codes is also required, although no previous experience with specific numerical tools is needed.

Dynamic design of machines

To fully understand the topics of this course, students need a good knowledge of the basic concepts of kinematics, force-momentum formulation for systems of particles and rigid bodies and static stress analysis. Students should also be familiar with work-energy concepts such as virtual work and Lagrange's equations. Basic skills in the use of relevant computer codes is also required, although no previous experience with specific numerical tools is necessary.

Dynamic design of machines

Here below is reported the Course Syllabus. Introduction to the course (2 hours). Mechanical design, static and dynamic stress analysis. Classical and numerical approach. Automatic computation in design. Numerical simulation. Computer aided engineering (CAE). Part 1 (9 hours of theory lectures, 6 hours of classroom exercise lectures). Overview on the dynamic analysis of linear systems. Discrete linear systems: equations of motion in the configuration space; equations in Lagrange form. State space. Block diagrams. Free behaviour of single and multi-d.o.f. systems. Modal uncoupling; modal participation factors. Forced response to harmonic excitation. Viscous, Viscoelastic, Electromagnetic, Structural damping. Systems with frequency dependent parameters. Forced response to non harmonic excitation; short account of random vibrations. Exercises addressing specific issues on the subject. Assignment of a project work dedicated to the fatigue design of mechanical parts in a mechanical subsystem affected by the vibration motion of the same subsystem. Part 2 (18 hours of theory lectures, 9 hours of classroom exercise lectures, 3 hours of laboratory experience). Numerical methods and discretization techniques. Lumped parameter methods, Finite element method in dynamics. Reduction techniques. Time domain and frequency domain solutions, numerical simulation. Specific exercises addressing the issues on the subject. Assignment of a project work dedicated to the design of a dynamic damper of a vibrating structure. Laboratory experience on the identification of the parameters of a vibrating structure. Part 3 (9 hours of lectures, 6 hours of exercises). Dynamics of rotating machines. Vibrations of rotors: Campbell diagram, critical speeds and fields of instability. Undamped and damped Jeffcott rotor. Rotor with 4 degrees of freedom, gyroscopic effect. Rotors with many degrees of freedom. Nonisotropic machines. Rotors on rolling, hydrodynamic and magnetic bearings. Balancing of rotors. Specific exercises addressing the issues on the subject. Part 4 (elective 7,5 hours of lectures, 3 hours of laboratory exercises). Short Outline in Controlled Electromagnetic and Electromechanical Systems: general considerations, open-loop control, closed-loop control, basic control laws, design of controlled systems. Specific exercises addressing the issues on the subject. Laboratory experience on the tuning of the control parameters of active magnetic bearings.

Dynamic design of machines

Here below is reported the Course Syllabus. Introduction to the course (1.5 hours). Static and dynamic stress analysis. Classical and numerical approach. Automatic computation in design. Numerical simulation. Part 1 (Lectures, 12 hours; classroom exercises, 6 hours). Overview on the dynamic analysis of linear systems. Discrete linear systems: equations of motion in the configuration space; equations in Lagrange form. State space. Block diagrams. Free behavior of single and multi-dof systems. Modal uncoupling; modal participation factors. Forced response to harmonic excitation. Viscous, Electromagnetic, Structural damping. Forced response to non-harmonic excitation, short account of random vibrations. Numerical exercises addressing specific issues on the subject. Assignment of a project work dedicated to the fatigue design of mechanical parts in a mechanical subsystem affected by the vibration motion of the same subsystem. Part 2 (Lectures, 12 hours; classroom exercises, 3 hours; laboratory experience, 3 hours). Numerical methods and discretization techniques. Lumped parameter methods, Finite element method in dynamics. Reduction techniques. Time domain and frequency domain solutions, numerical simulation. Specific exercises addressing the issues on the subject. Assignment of a project work dedicated to the design of a dynamic damper of a vibrating structure. Laboratory experience on the identification of the parameters of a vibrating structure. Part 4 (Lectures, 7.5 hours; classroom exercises, 3 hours; laboratory experience, 3 hours). Short Outline in Controlled Electromagnetic and Electromechanical Systems: general considerations, open-loop control, closed-loop control, basic control laws, design of controlled systems. Specific exercises addressing the issues on the subject. Laboratory experience on the tuning of the control parameters of active magnetic bearings. Part 3 (Lectures, 6 hours; classroom exercises, 3 hours). Dynamics of rotating machines. Vibrations of rotors: Campbell diagram, critical speeds and fields of instability. Undamped and damped Jeffcott rotor. Specific exercises addressing the issues on the subject.

Dynamic design of machines

Dynamic design of machines

Dynamic design of machines

The subject is based on a total of 38 hours of lectures plus 24 hours of classroom and laboratory exercises. Lectures will be held with the support of the blackboard, slides and notes. The exercise classes will deal with a number of exercises aimed to a better understanding of the subjects dealt with during theoretical classes and in a number of projects, the students will prepare in team. The technical reports on the projects will deal specific problems of dynamic structural analysis related to specific machine elements. Some of these exercises will be performed in a computer lab, using specific numerical tools, while others will be performed in the experimental lab. The documentation used during the theoretical classes and the exercises will be made available to the students through the website.

Dynamic design of machines

The overall course includes 39 hours of lessons and 21 hours shared between classroom exercises (Tutorial) and laboratory exercises. Lectures take place with the support of the blackboard, slides and notes. Tutorials aim to a better understanding of the subjects covered during the lessons. The activities indicated as “Project” deal with specific dynamic problems related to the elements of the machine. The technical Reports on the Projects will be discussed during the oral exam. We recommend that students join a team of 2/3 people team to prepare the Technical Reports. The documentation used during the theoretical lessons and the tutorial will be made available to the students through the website.

Dynamic design of machines

The textbook for the subject is: Genta G., Vibration Dynamics and Control, Springer, New York, 2009, ISBN 978 0 387 79579 9 or, alternatively, , Genta G., Vibrazioni delle strutture e delle macchine, Levrotto e Bella, Torino, 1996. Other textbooks that can be used for specific parts of the course are Genta G, Vibration of structures and machines, III ed., Springer, New York, 1998, ISBN: 0 387 98506 9 and Genta G., Dynamics of Rotating Systems, Springer, New York, 2005 ISBN: 0-387-20936-0. Additional material for exercises will be supplied through the subject website.

Dynamic design of machines

The textbook for the subject is: Genta G., Vibration Dynamics and Control, Springer, New York, 2009, ISBN 978 0 387 79579 9 or, Genta G., Vibrazioni delle strutture e delle macchine, Levrotto e Bella, Torino, 1996. Other textbooks that can be used for specific parts of the course are Genta G, Vibration of structures and machines, III ed., Springer, New York, 1998, ISBN: 0 387 98506 9 and Genta G., Dynamics of Rotating Systems, Springer, New York, 2005 ISBN: 0-387-20936-0. Additional material for exercises will be supplied through the subject website.

Dynamic design of machines

**Modalità di esame:** Prova scritta (in aula); Prova orale obbligatoria; Elaborato scritto prodotto in gruppo;

Dynamic design of machines

**Exam:** Written test; Compulsory oral exam; Group essay;

Dynamic design of machines

The assessment will include a written test followed by an oral examination. To be allowed to the oral exam the student must have passed the written test with at least 18/30 rating. Written test The written test will consist of 30 multiple choice tests (correct answer: 1 point; no answer 0 points; wrong answer: -0.5 points) plus 8 exercises (correct answer: 2 points; no or wrong answer: 0 points) to be answered in 2 hours. At least 15 tests and 4 exercises must be answered. No books, notes or other material are allowed at the written test. Use of a cell phone or other communication device will cause immediate expulsion. Oral exam If the rating of the written test is between 18/30 and 23/30 (included) the oral exam may be substituted by a discussion on the project report. This can produce an increase or a decrease of the rating up to 2 points, depending on how the project are made. A complete failure of answering questions about the project report causes a failure of the exam. If the student aims to obtain more than 23/30 or he has answered less than 15 tests and 4 exercises the oral exam is compulsory. If the rating of the written test is in between 24/30 and 30/30 the oral exam is compulsory. The oral exam includes at any rate a discussion on the project reports. A failure of answering the questions on the project reports or the presentation of incomplete projects causes a complete failure of the exam. It is recommended to book the exam only when there is a reasonable expectation to actually giving the exam. The exam rules stated for the past years will apply to students who have followed the course in the past.

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.

Dynamic design of machines

**Exam:** Written test; Compulsory oral exam; Group essay;

Dynamic design of machines

At the end of the course the assessment of learning is performed with an exam consisting of a written and an oral test. The written test has a total duration of 2 hours. The oral test lasts approximately 30 minutes. If students wish to withdraw from the examination they have to inform one of the examiner before the end of the written test. The evaluation of the exam is assessed according to the following criteria: -) Exhaustive and complete knowledge of the subject combined with an excellent ability to understand and solve a problem applying concepts and tools developed during the course, outstanding capability to establish disciplinary and multidisciplinary links and to critically review the work done and the results obtained: 30/30 with honors (cum laude). -) Very good knowledge of the subject and good skills; good ability to understand and solve problems related to the structure dynamics, good capacity to make disciplinary and multidisciplinary connections: 26/30. -) Correct knowledge and sufficient skills; good understanding and application of knowledge: 22/30. -) Sufficient knowledge of the main aspects of the topics and essential skills while making minor mistakes: 18/30. -) Incomplete knowledge and insufficient skills; knowledge applied incompletely and inaccurately; errors and deficiency in critical thinking: 14/30. -) Serious gaps in knowledge and skills; major errors in understanding and finding solutions; serious shortcomings during the logical revision phase: 8/30. -) Completely missing or fragmented knowledge and skills; insufficient understanding of the problem and inability to find an adequate solution; lack of logical thinking and incapacity to review the work done: 2/30 The exam score is shared between the written test (max 24 points), the oral exam (max 4 points) and the discussion of the Projects (max 4 points). The final score is given by the sum of the three parts. Scores of 32 points will be reported as 30/30 with honors (cum laude). The written test consists of three questions related to the theoretical part and the application of the theory (i.e. 2 open questions on theory + 1 exercise or 1 open question about theory + 2 exercises). To take the oral exam the student must have passed the written test with at least 18/30 (14/24 according to the maximum score of the written test). During the exam books, notes or other auxiliary material on any media are not allowed. Students must not have mobile phones, smart watches or other communication devices. Students will discuss their Projects during the oral exam, then students will attend the Projects discussion with a copy (printed or electronic-copy) of their own Projects. The examiner will evaluate the completeness and correctness of the Projects technical reports and the students’ ability to explain their Projects in detail.

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.

Dynamic design of machines

**Modalità di esame:** Prova orale obbligatoria; Elaborato scritto prodotto in gruppo; Prova scritta su carta con videosorveglianza dei docenti;

Dynamic design of machines

At the end of the course the assessment of learning is performed with an exam made of a written and an oral test. The exam evaluation is given according to the following criteria: Through and complete knowledge of the subject combined with an excellent ability to understand and solve a problem applying concepts and tools developed during the course, outstanding capability to establish disciplinary and multidisciplinary links and to critically review the work done and the results obtained: 30/30 with honors (cum laude). Very good knowledge of the subject and good skills; good ability to understand and solve problems related to the structure dynamics, good capacity to make disciplinary and multidisciplinary connections: 26/30. Correct knowledge and skills; good understanding and application of knowledge: 22/30. Sufficient knowledge of the main aspects of the topics and essential skills while making minor mistakes: 18/30. Incomplete knowledge and skills; knowledge applied incompletely and inaccurately; errors and logical deficiencies: 12/30. Serious gaps in knowledge and skills; significant errors in understanding and finding solutions; serious shortcomings during the logical revision phase: 8/30. Knowledge and skills completely missing or fragmented; insufficient understanding of the problem and inability to find a proper solution; lack of logic and revision capacity: 2/30 The exam score is shared between the written test (max 24 points), the oral exam (max 6 points) and the discussion of the Projects (max 2 points). The final score is given by the sum of the three parts. Scores of 32 points will be reported as 30/30 with honors (cum laude). The written test consists of three issues related to the theoretical part and the application of the theory (i.e. 2 open questions about theoretical part + 1 exercise or 1 open question about theoretical + 2 exercises). To take the oral exam the student must have passed the written test with at least 18/30 (14/24 according to the maximum score of the written test). During the exam books, notes or other auxiliary material on any media are not allowed. Students must not have mobile phones, smart watches or other communication devices. Students will discuss their projects during the oral exam. The examiner will evaluate the completeness and correctness of the Projects technical reports and the students’ ability to explain their Projects in detail.

Dynamic design of machines

**Exam:** Compulsory oral exam; Group essay; Paper-based written test with video surveillance of the teaching staff;

Dynamic design of machines

At the end of the course the assessment of learning is performed with an exam consisting of a written and an oral test. The written test has a total duration of 2 hours. The oral test lasts approximately 30 minutes. If students wish to withdraw from the examination they have to inform one of the examiner before the end of the written test. The evaluation of the exam is assessed according to the following criteria: -) Exhaustive and complete knowledge of the subject combined with an excellent ability to understand and solve a problem applying concepts and tools developed during the course, outstanding capability to establish disciplinary and multidisciplinary links and to critically review the work done and the results obtained: 30/30 with honors (cum laude). -) Very good knowledge of the subject and good skills; good ability to understand and solve problems related to the structure dynamics, good capacity to make disciplinary and multidisciplinary connections: 26/30. -) Correct knowledge and sufficient skills; good understanding and application of knowledge: 22/30. -) Sufficient knowledge of the main aspects of the topics and essential skills while making minor mistakes: 18/30. -) Incomplete knowledge and insufficient skills; knowledge applied incompletely and inaccurately; errors and deficiency in critical thinking: 14/30. -) Serious gaps in knowledge and skills; major errors in understanding and finding solutions; serious shortcomings during the logical revision phase: 8/30. -) Completely missing or fragmented knowledge and skills; insufficient understanding of the problem and inability to find an adequate solution; lack of logical thinking and incapacity to review the work done: 2/30 The exam score is shared between the written test (max 24 points), the oral exam on the theoretical part (max 4 points) and the discussion of the Projects (max 4 points). The final score is given by the sum of the three parts. Scores of 32 points will be reported as 30/30 with honors (cum laude). The written test consists of three questions related to the theoretical part and the application of the theory (i.e. 2 open questions on theory + 1 exercise or 1 open question about theory + 2 exercises). To take the oral exam the student must have passed the written test with at least 18/30 (14/24 according to the maximum score of the written test). During the exam books, notes or other auxiliary material on any media are not allowed. Students must not have mobile phones, smart watches or other communication devices. Students will discuss their Projects during the oral exam, then students will attend the Projects discussion with a copy (printed or electronic-copy) of their own Projects. The examiner will evaluate the completeness and correctness of the Projects technical reports and the students’ ability to explain their Projects in detail.

Dynamic design of machines

**Modalità di esame:** Prova scritta (in aula); Prova orale obbligatoria; Elaborato scritto prodotto in gruppo; Prova scritta su carta con videosorveglianza dei docenti;

Dynamic design of machines

At the end of the course the assessment of learning is performed with an exam consisting of a written and an oral test. The evaluation of the exam is assessed according to the following criteria: -) Exhaustive and complete knowledge of the subject combined with an excellent ability to understand and solve a problem applying concepts and tools developed during the course, outstanding capability to establish disciplinary and multidisciplinary links and to critically review the work done and the results obtained: 30/30 with honors (cum laude). -) Very good knowledge of the subject and good skills; good ability to understand and solve problems related to the structure dynamics, good capacity to make disciplinary and multidisciplinary connections: 26/30. -) Correct knowledge and sufficient skills; good understanding and application of knowledge: 22/30. -) Sufficient knowledge of the main aspects of the topics and essential skills while making minor mistakes: 18/30. -) Incomplete knowledge and insufficient skills; knowledge applied incompletely and inaccurately; errors and deficiency in critical thinking: 14/30. -) Serious gaps in knowledge and skills; major errors in understanding and finding solutions; serious shortcomings during the logical revision phase: 8/30. -) Completely missing or fragmented knowledge and skills; insufficient understanding of the problem and inability to find an adequate solution; lack of logical thinking and incapacity to review the work done: 2/30 The exam score is shared between the written test (max 24 points), the oral exam (max 6 points) and the discussion of the Projects (max 2 points). The final score is given by the sum of the three parts. Scores of 32 points will be reported as 30/30 with honors (cum laude). The written test consists of three questions related to the theoretical part and the application of the theory (i.e. 2 open questions on theory + 1 exercise or 1 open question about theory + 2 exercises). To take the oral exam the student must have passed the written test with at least 18/30 (14/24 according to the maximum score of the written test). During the exam books, notes or other auxiliary material on any media are not allowed. Students must not have mobile phones, smart watches or other communication devices. Students are going to discuss their Projects during the oral exam. The examiner will evaluate the completeness and correctness of the Projects technical reports and the students’ ability to explain their Projects in detail.

Dynamic design of machines

**Exam:** Written test; Compulsory oral exam; Group essay; Paper-based written test with video surveillance of the teaching staff;

Dynamic design of machines

At the end of the course the assessment of learning is performed with an exam consisting of a written and an oral test. The written test has a total duration of 2 hours. The oral test lasts approximately 30 minutes. If students wish to withdraw from the examination they have to inform one of the examiner before the end of the written test. The evaluation of the exam is assessed according to the following criteria: -) Exhaustive and complete knowledge of the subject combined with an excellent ability to understand and solve a problem applying concepts and tools developed during the course, outstanding capability to establish disciplinary and multidisciplinary links and to critically review the work done and the results obtained: 30/30 with honors (cum laude). -) Very good knowledge of the subject and good skills; good ability to understand and solve problems related to the structure dynamics, good capacity to make disciplinary and multidisciplinary connections: 26/30. -) Correct knowledge and sufficient skills; good understanding and application of knowledge: 22/30. -) Sufficient knowledge of the main aspects of the topics and essential skills while making minor mistakes: 18/30. -) Incomplete knowledge and insufficient skills; knowledge applied incompletely and inaccurately; errors and deficiency in critical thinking: 14/30. -) Serious gaps in knowledge and skills; major errors in understanding and finding solutions; serious shortcomings during the logical revision phase: 8/30. -) Completely missing or fragmented knowledge and skills; insufficient understanding of the problem and inability to find an adequate solution; lack of logical thinking and incapacity to review the work done: 2/30 The exam score is shared between the written test (max 24 points), the oral exam on the theoretical part (max 4 points) and the discussion of the Projects (max 4 points). The final score is given by the sum of the three parts. Scores of 32 points will be reported as 30/30 with honors (cum laude). The written test consists of three questions related to the theoretical part and the application of the theory (i.e. 2 open questions on theory + 1 exercise or 1 open question about theory + 2 exercises). To take the oral exam the student must have passed the written test with at least 18/30 (14/24 according to the maximum score of the written test). During the exam books, notes or other auxiliary material on any media are not allowed. Students must not have mobile phones, smart watches or other communication devices. Students will discuss their Projects during the oral exam, then students will attend the Projects discussion with a copy (printed or electronic-copy) of their own Projects. The examiner will evaluate the completeness and correctness of the Projects technical reports and the students’ ability to explain their Projects in detail.

© Politecnico di Torino

Corso Duca degli Abruzzi, 24 - 10129 Torino, ITALY

Corso Duca degli Abruzzi, 24 - 10129 Torino, ITALY