Kinematics and Dynamics of Machines

ME25C09:

Kinematics and Dynamics of Machines

Course Objectives:

The course introduces the fundamental concepts of mechanical linkages and mechanisms used in machines, including higher pairs such as cams and gear transmissions. It develops an understanding of force analysis in mechanisms, the effects of unbalanced forces, and the basic principles governing vibrations in mechanical systems.

Kinematic Analysis in Simple Mechanisms and Cams: Mechanisms, Terminology and definitions, kinematics inversions of 4 bar and slide crank chain, kinematics analysis in simple mechanisms, velocity and acceleration polygons.

Practical: Analysis of Four Bar Chain and Slider Crank Mechanisms,

Cams: Cam-terminology, different types of cams and followers, Cam design for different follower motion curves, graphical construction of cam profiles for different types of followers.

Practical: Cam displacement curves.

Gears and Geartrains: Gear terminology, law of toothed gearing, involute gearing, Gear tooth action, Interference and undercutting, geartrains, parallel axis gear trains, Epicyclic geartrains.

Practical: Experimental study of velocity ratios of simple, compound, Epicyclic and differential gear trains.

Static and Dynamic Force Analysis: Applied and Constrained Forces, Free body diagrams, Static equilibrium conditions, Static Force analysis in simple mechanisms, Dynamic Force Analysis in simple machine members, Inertia Forces and Inertia Torque, D’Alembert’s principle.

Balancing of Rotating Masses and Gyroscope: Static and Dynamic balancing, Balancing of revolving masses, Balancing machines, Gyroscopes, Gyroscopic Couple, Gyroscopic stabilization, Gyroscopic effects in Automobiles, ships and airplanes.

Practical: Motorized gyroscope, Study of gyroscopic effect and couple.

Mechanical Vibrations: Vibrations-single degree of freedom system, equations of motion-undamped and damped free vibration of single degree of freedom system, logarithmic decrement, Forced vibration of single degree of freedom system, magnification factor, rotating unbalance-support harmonic excitation, critical speed of shafts

Practical:

• Undamped free vibrations of a single degree freedom spring-mass system.

• Torsional Vibration (Undamped) of single rotor shaft system

• Determination of critical speed of shafts.

Tasks:

T1. Design a four-bar mechanism for an application such as a windshield wiper or robotic arm to achieve a desired motion path.

T2. Design a cam and follower system for an IC engine valve mechanism to achieve specified motion (displacement, velocity, acceleration).

T3. Design a gear train system (simple or epicyclic) for an automobile gearbox or industrial machine to obtain required speed reduction and torque transmission.

T4. Analyze and design a rotating system (shaft with masses) for proper balancing and determine the critical speed to avoid excessive vibration in machines (e.g., turbine shaft or motor rotor).

Weightage: Continuous Assessment: 50%, End Semester Examinations: 50%.

Assessment Methodology: Written Test (40%), Practical (30%), Activity (30%).

Practical: Lab Experiments (50%), Tasks (50%) (Each student must complete a minimum of two tasks).

Activity: Review of GATE/ESE Questions (10%), Mini Project/ Quiz/ Assignment Programs/ Flipped Class /Seminar Presentation (20%)

References:

1. S. S. Rattan, Theory of Machines, 5th Edition, McGraw Hill, 2019.

2. J. J. Uicker Jr., G. R. Pennock & J. E. Shigley, Theory of Machines and Mechanisms, 6th Edition, Cambridge University Press, 2023.

3. P. L. Ballaney, Theory of Machines and Mechanisms, 26th Edition, Khanna Publishers, 2024.

4. R. L. Norton, Kinematics and Dynamics of Machinery, 3rd Edition (SI Units), McGraw Hill Education, 2020.