88153 - Mechanical Actuators P

Learning outcomes

1. Dissipative actions in machine components

Kinetic friction and Static friction. Wear: Reye hypothesis; distribution of contact pressure. Rolling friction: applications of rolling contact. Rolling bearings: choice and applications.

2. Functional analysis of power transmissions

Gears: involute profiles; geometrical parameters; cylindrical spur gears and helical gears; force transmission; bevel gears; worm gears. Gear trains: ordinary gears; epicyclic trains; differential trains. Change gears. Transmission of motion between two shafts: belt drives; transmissions with chains.

3. Functional analysis of devices connecting two shafts

Brakes: classification; block brakes; brake torque. Clutches: classification; disk friction clutches; conical friction clutches. Couplers: classification; solid couplings; Oldham’s joint; Hooke's joint; constant velocity joints; flexible joints.

4. Dynamic analysis of machines

Fundamental equation of dynamics: kinetic energy; energy equation. Metodi energetici per lo studio della dinamica di sistemi di corpi rigidi. Dynamics of the slider crank mechanism: calculation; methods for the compensation of inertia actions. Dynamics of the four-bar linkage. Rotor dynamics: static and dynamic imbalance.

5. Mechanical vibrations

Mass-spring-damper model. Free and forced vibration response of one degree-of-freedom system. Free and forced vibration response of two dof systems. Applications: reduction of the force to the ground; reduction of vibrations generated by a vibrating ground; mass damper;

Course contents

1. FUNAIOLI E., MAGGIORE A., MENEGHETTI U., Lezioni di Meccanica Applicata alle Macchine. Prima parte: Fondamenti di Meccanica delle Macchine, ed. Pàtron, Bologna.
   
   
2. Callegari M., Fanghella P., Pellicano F., Meccanica Applicata alle Macchine, CittàStudi, 2013
   
   
3. Supplementary materials (diagrams and slides employed during lectures).

Readings/Bibliography

The course is based on lectures dealing with the theoretical aspects of the course topics and application examples.

Class attendance, although not mandatory, plays a fundamental role in the learning and evaluation process.

Teaching methods

The final examination consists of questions that aim to ensure the acquisition of knowledge expected by the course program and to assess the achievement of learning objectives.

Both oral and written questions might be proposed during the examination.

The ability of the student to articulate and correctly explain the answers to the questions, has a fundamental weight in the attribution of the final marks.

In accordance with the Art. 16 of the University Didactic Regulations, if a positive grade does not meet the expectations of a student, the latter may ask its cancellation and the repetition of the examination. The instructors of the course comply with the following rules:

• a student may request the cancellation of a positive grade only within the date of the examination;
• a cancelled positive grade can in no way be recovered;
• a student may request the cancellation of a positive grade at most once.

Assessment methods

The exam consists of solving a few simple problems to verify the student’s knowledge of the course material.

During the exam, at the discretion of the examination committee, questions may be presented in written and/or oral form.

Specifically, the purpose of the exam is to assess whether the educational objectives of the course have been achieved, namely:

• basic knowledge of the functioning and modeling of the main mechanical components used in machinery;
• understanding of the fundamental tools for analyzing dynamics, machinery, and mechanical vibrations.

The student’s ability to approach problem-solving and/or to clearly and accurately articulate answers to questions serves as the primary basis for grading. Demonstrating an exceptional level of in-depth study may be considered an important factor for awarding honors.

In accordance with Article 16 of the current Academic Regulations, a negative evaluation does not result in the assignment of a grade. In the case of a positive outcome, the grade may be declined at most once.

Teaching tools

Blackboard, PC.

On the E-learning Platform (https://virtuale.unibo.it/ ), students may find: slides of the course lectures; exercises and application examples.

Office hours

See the website of Lorenzo Agostini