Theory of Mechanism and Machine

Course objective
To make student understand about different mechanism used in devices or machines and make them able to do complete analysis of mechanism (including linkage, gears, gear trains, cam and followers). To provide the students with basic concept of dynamics response analysis of mechanism and their vibratory response.

1. Introduction to linkage and mechanisms (4 hours)
1. Introduction to the study of mechanism, mobility, degree of freedom
2. Mechanism configuration, linkages, chains, inversions
3. Introduction to different mechanism: slider crank, scotch yoke, quick return, toggle, Oldham coupling & Hooke’s coupling, straight line, chamber wheel, constant velocity universal joint, intermittent motion, mechanical compounding
4. Position analysis of four bar and slider crank mechanism
5. Four bar linkage motion and Grashoff’s law
6. Linkage position analysis; loop closure equipment & iterative methods
7. Synthesis concepts


2. Kinematics analysis of mechanisms (6 hours)
1. General plane motion representation.
2. Relative motion using velocity polygon: graphical and vector algebra solution
3. Instantaneous centre of velocity and Kennedy’s theorem
4. Relative motion using acceleration polygon: graphical and vector algebra solution, Coriolis acceleration
5. Motion analysis by vector mathematics: velocity analysis, acceleration analysis, Coriolis acceleration


3. Cam and followers (4 hours)
1. Classification of cam and nomenclature
2. Graphical cam layout
3. Disk cam with flat-faced, radial and offset followers
4. Standardized followers displacement or lift curve
5. Analytical design of disk cam with flat, radial and offset, oscillating roller followers
6. Cam production methods


4. Gear and gear trains (8 hours)
1. Introduction and classification of gears
2. Geometry of involute gears: spur, bevel, helical and worm
3. Characteristics of involute tooth action
4. Interference of involute gears and number of teeth to avoid interference
5. Non-standard spur gears representing extended centre distance system
6. Gear train: introduction and classification
7. Theory and assembly: planetary gear and differential gear
8. Speed ratios: formula and tabular method for spur and bevel gears.


5. Force analysis of mechanisms (6 hours)
1. Centrifugal force, inertia force and inertia torque
2. Methods of force analysis
3. Force analysis on four bar and slider crank mechanism
4. Piston and connecting rod
5. Force analysis on gear teeth: spur, bevel and helical gears
6. Force analysis on cams & followers
7. Superposition force analysis: graphical and analytical methods


6. Gyroscopic couples, flywheel and governors (4 hours)
1. Gyroscopic couples and its application
2. Stability of a two wheel and four wheel vehicles
3. Turning moment diagram and flywheel sizing
4. Governors: types, functions and characteristics


7. Dynamic balancing (4 hours)
1. Balancing of rotating mass
2. Balancing of reciprocating mass
3. Balancing of multi cylinder engine: in-line, V-type, opposed and radial configuration
4. Balancing of four bar linkage
5. Types of balancing machine


8. Vibrations (10 hours)
1. Introduction to vibration
2. Element of vibrating systems
3. Vibration of single degree of freedom: undamped, damped and forced with examples
4. Vibration due to unbalance
5. Whirling of rotating shaft
6. Vibration isolation and force transmissibility
7. Vibration of multi degree of freedom: undamped, damped and forced
8. Vibration of continuous system: lateral vibration in string, longitudinal vibration in rod, torsional oscillation in circular shaft, lateral vibration in beams
9. Vibration absorber

Practical

1. Experiment of gyroscope
2. Balancing of rotating mass
3. Response of spring mass system
4. Response of different types of governors
5. Whirling of a rotating shaft

References

1. “Theory of Mechanics and Mechanism”, J.E.Shigley and J.J. Uicker, Jr. Mc Graw Hill, (Latest in 2011).
2. “Theory of machines”, S.S. Rattan, Tata Mc Graw Hill Education private Limited, New Delhi (Third edition).
3. “Mechanism and Machine Theory”, J.S. Rao & R.V. Dukkipati (Latest in 2011).
4. “Mechanism and Dynamics of Machinery”, H.H. Mabie and C. F. Reinholtz, Wiley. (Latest in 2011).
5. “Kinematics and Dynamics of Planar Machinery”, B. PaiSI, Prentice Hall (Latest in 2011).
6. C. E. Wison, J. P. Sadler and W. J. Michels, “Kinematics and Dynamics of Machinery”, Harper Row, (Latest in 2011).
7. Dr. Sidhu Singh; “Kinematics of Machines/Dynamics of Machines”.
8. “Theory of Vibration with applications”, W.T. Thomson, Printace Hall.
9. “Mechanical Vibrations”, S. S Rao, Addition Wasley.
10. ‘‘Fundamental of Mechanical Vibrations”, S.G. Kelly, Mc Graw Hill.

Evaluation scheme
The questions will cover all the chapters of the syllabus. The evaluation scheme will be as indicated in the table below: