# ME 226 : Mechanical Measurements

Course Name and Code

Mechanical Measurements (ME 226)

Course Instructor

Prof Amit Agrawal and Prof S. V. Prabhu

Description

Metrology is an essential element in an engineer’s life. No idea or design holds credit until implemented and proven. Two tools are vital to prove the efficiency of a design – Measurements and Statistics. Having learnt the latter already in ME 102, in this course, the students are exposed to the theory and general thought process that goes into designing various measurement devices.

In this course, we will first learn to broadly classify transformation systems and then analyse various simple and complex measuring devices using this classification. The course will also familiarise students with the mathematics and laws behind some specific measurement instruments such as thermocouples and strain gauges. This course is generally taught by Prof Amit Agrawal and Prof S. V. Prabhu. Though the course content taken up by both professors is largely the same, the courses vary considerably from each other.

Course Content

1)Dynamic Characteristics of Measurement Systems

– Revision of statistics

– General structure of a measurement system

– General input – output equation

– Study of a first and second order system subjected to various inputs (step, ramp, impulse, sinusoidal)

– Basic Fourier Series implementation

2)Temperature Measurement: Thermocouples, thermometers, resistance temperature detectors etc.

3)Pressure Measurement: Manometers, pressure gauges, diaphragms, Pitot tubes, etc.

4)Flow Rate Measurement: Differential pressure devices (Orificemeters, Venturimeters, etc), vortex flow meter, etc.

5)Force Measurement: Weighing balances, load cells, strain gauges, etc.

6)Motion Measurement: Elastic transducers, Linear Vairable Differential Transformer, etc.

7)Measurement of Strain: Strain gauges in various arrangements.

8)Operational Amplifiers: Integrators, Differentiators, Difference amplifiers, etc. (Prabhu)

9)Particle image velocimetry (Amit Agrawal)

10)Gyroscope analysis (Amit Agrawal)

Again, even if the bullet points are the same, the approaches taken by both the professors are very different. With Prabhu, it will be more about modelling and analysis and fairly well defined numericals, though he does put up some interestingly thought provoking questions at times. With Amit Agrawal, the approach is very open-ended, the professor tries to give the students a feel for these systems and tries to make them think with in his exams, but his teaching can get a little too vague and lacks structure, starkly in contrast with Prabhu.

With Prabhu, it is the standard 2 quizzes, one midsem and one endsem. The grading is decent with a healthy number of AAs, ABs and BBs.

With Amit Agrawal, there are 4 to 5 quizzes, mid-sem and endsem in addition to one or two projects. The grading was strict and so this should not be mistaken to be an easy AA course.

Both professors are very strict about attendance.

Motivation

Whether it is conducting experiments for R&D, or testing product quality in industry, measurements play a vital role in the life of a mechanical engineer. Also, designing an accurate, consistent measuring device is not as trivial a task as it sounds to be. Thus, this turns out to be a vital as well as an intriguing course.

Resources

1) Doebelin’s Measurement Systems by Ernest Doebelin and Dhanesh Manik

2) Measurement Systems 5th Edition by Ernest Doebelin

Book 1 is the adapted version of book 2. Book 1 is recommended because in addition to the theory it also contains many solved problems and has practise problems also.