MECHANICAL AND THERMAL MEASUREMENTS
Academic Year 2022/2023 - Teacher: Fabio Raffaele Emilio An LO SAVIOExpected Learning Outcomes
The course aims to provide basic measurement knowledge and an accurate
transducers analysis. It deals with both static and dynamic analysis of
the performance of the measurement chains. The main types of transducers
are analyzed in detail with the discussion of the metrological
parameters. The student engineer will be instructed on the most
significant aspects of measuring devices and methods for detecting the
main mechanical and thermal quantities. The course also includes
practical exercises in the laboratory and in the classroom with examples
of the use of sensors and data analysis.
Course Structure
Frontal teaching in the classroom or in the laboratory.
Required Prerequisites
No prerequisites are required.
Attendance of Lessons
As foreseen by the University Regulations, a minimum attendance of 70% of the hours of lessons is required.
Detailed Course Content
Rationale for measurement operations. Concepts of magnitude and
measure. Units of measurement systems: CGS, MKS, Technical System,
English System, International System. Dimensional equations. Measurement
schemes: direct, indirect, zeroing and deviation instruments. Theory of measurement systems: aim
of the measurement; functional analysis of an instrument; active and
passive transducers; flow of information in the measurement chain;
errors due to disturbing factors. Statistical analysis for the "a posteriori" evaluation of uncertainties:
representation of errors; best value, standard deviation and standard
deviation of the mean; Gauss curve; error propagation; Chauvenet
criterion; least squares method (linear regression), covariance and
correlation. Static performance of instruments: static
calibration; metrological characteristics and causes of error of the
instruments: sensitivity; linearity; repeatability; accuracy; precision;
fineness (insertion error); hysteresis; mobility and resolution. Dynamic performance of instruments: response to time-varying signals; bandwidth; instruments of 0, 1 and 2-order; transfer function; dynamic calibration. Analog circuits and instruments: Wheatstone bridge; potentiometric circuit; galvanometer; oscilloscope. Measurement of the main mechanical quantities:
length and displacement; speed and flow; vibration and acceleration;
mass and strength; temperature; mechanical power; pressure. Stress-strain analysis: local methods (strain gauge measurements).
Textbook Information
1. E. O. Doebelin, Instruments and methods of measurement, McGraw-Hill. Milan.
2. A. Ajovalasit, Stress analysis: strain gauge. University of Palermo.
3. J.R. Taylor, Introduction to error analysis, Zanichelli.
Lecture notes and slides by the teacher.
2. A. Ajovalasit, Stress analysis: strain gauge. University of Palermo.
3. J.R. Taylor, Introduction to error analysis, Zanichelli.
Lecture notes and slides by the teacher.
Course Planning
| Subjects | Text References | |
|---|---|---|
| 1 | Metrology and theory of errors. | [3] and lecture notes by the teacher |
| 2 | Analog circuits and instruments. | [1] and lecture notes by the teacher |
| 3 | Measurement of the main mechanical quantities. | [1] and lecture notes by the teacher |
| 4 | Extensimetry. | [2] and lecture notes by the teacher |
Learning Assessment
Learning Assessment Procedures
The exam consists of an oral test.
During the lessons, applicative exercises of the course contents are carried out in the laboratory and in the classroom aimed at learning the practical experimentation by the students.
The laboratory exercises, each described in the form of a technical report, and the topics covered during the lessons are discussed during the oral exam.
The assessment during the oral test will be based on: knowledge of the topics covered, the relevance of the answers to the questions posed, the property of technical language, the ability to make connections between the contents of the program.
During the lessons, applicative exercises of the course contents are carried out in the laboratory and in the classroom aimed at learning the practical experimentation by the students.
The laboratory exercises, each described in the form of a technical report, and the topics covered during the lessons are discussed during the oral exam.
The assessment during the oral test will be based on: knowledge of the topics covered, the relevance of the answers to the questions posed, the property of technical language, the ability to make connections between the contents of the program.
Examples of frequently asked questions and / or exercises
Candidate describes how to normalize a Gauss curve.
The Candidate explains the basic laws of thermocouples.
The Candidate describes the best configurations for measuring bending with strain gauges.
The Candidate explains the theory of interferometry and the application in the interferometric bench.
The Candidate explains the basic laws of thermocouples.
The Candidate describes the best configurations for measuring bending with strain gauges.
The Candidate explains the theory of interferometry and the application in the interferometric bench.