Unit Description and General Aims

The objective in presenting this unit is to provide students with broad knowledge of the functions of machines/mechanisms – as a necessity for optimum machine design – and the fundamental principles of simple machine elements – which are frequently employed as devices in modern complex machines.

The subject matter covered in this unit will include: the different types of links and joints making up mechanisms; velocity and acceleration analysis; static and dynamic force analysis; design and analysis of cams, gears, drive trains, and flywheels; the characteristics of belt and chain drives, balancing techniques for rotating and reciprocating masses; and, an overview of vibrations.

At the conclusion of this unit, students will have been imparted with relevant knowledge to assist them in analyzing, designing, selecting, and evaluating mechanisms for various applications.

Learning Outcomes

On successful completion of this Unit, students are expected to be able to:

1. Analyse displacement, velocity and acceleration of planar mechanisms 
   Bloom's Level 4

2. Analyse static and dynamic forces on planar mechanisms
   Bloom's Level 4

3. Evaluate kinematics of belts, chains, gears, gear trains, cams and flywheels  
   Bloom's Level 5

4. Construct and solve balancing calculations for rotating and reciprocating machinery 
   Bloom's Level 6

5. Analyse vibrational response of simple single-degree-of-freedom systems
   Bloom's Level 4

Student assessment

Overall requirements: Students must achieve a result of 40% or above in the exam itself to pass the exam, and must pass the exam to be able to pass the unit. An overall final unit score of 50% or above must be achieved to pass the unit assessment.

Prescribed and Recommended Readings

Suggested Textbook 

1. Cleghorn, W., & Dechev, N. (2014). Mechanics of Machines (2nd edition). Oxford University Press.
2. Rattan, S. S. (2019). Theory of machines. Tata McGraw-Hill Education.

 Reference Materials

• D. H. Myszka, Machines and Mechanisms, Applied Kinematic Analysis, 4th ed. Prentice Hall. ISBN 9780132157803
• Ryder, G. H., & Bennett, M. D. (1990). Mechanics of machines. Industrial Press Inc..
• Wilson, CE, Sadler, JP 2003, Kinematics and Dynamics of Machinery, 3rd edn, Prentice Hall, ISBN-13: 978-0201350999
• Waldron KJ, Kinzel, GL 2003, Kinematics, Dynamics, and Design of Machinery, 2nd edn, John Wiley & Sons Inc., ISBN-13: 978-0471244172

Unit Content

Topic 1

Introduction to Kinematics and Mechanisms

1. Commonly employed mechanisms

2. Planar and spatial mechanisms

3. Kinematic chains and kinematic pairs

4. Mechanism mobility

5. Mechanism inversion

6. Types of four-bar and slider-crank mechanisms

Topic 2

Mechanics of rigid bodies and Planar Mechanisms

1. Position Analysis

2. Displacement Analysis

3. Limit positions and time ratio of mechanisms

4. Transmission angle

5. Kinematics of a point using Cartesian Coordinates

6. Kinematics of a point using Radial – Transverse Coordinates

Topic 3

Velocity Analysis of Planar Mechanisms

1. Relative velocity between two points undergoing planar motion

2. Special cases of relative velocity expression

3. Velocity analysis of four bar mechanism, slider crank mechanism, and simple mechanisms by vector polygons

4. Angular velocity of links

5. Velocity of rubbing

Topic 4

Acceleration Analysis of Planar Mechanisms

1. Relative acceleration between two points undergoing planar motion

2. Special cases of relative acceleration expression

3. Acceleration analysis of four bar mechanism, slider crank mechanism, and simple mechanisms by vector polygons

4. Coriolis component of acceleration

5. Angular acceleration of links

Topic 5

Static and Dynamic Force Analysis of Planar Mechanisms

1. Kinetics

2. Equations of Equilibrium

3. Two-Force member

4. Three-Force member

5. Force transmission in frictionless kinematic pairs

6. Force polygons

7. Static force analysis using force polygon method

8. Principle of superposition

9. Graphical dynamic force analysis of a link – inertia circle

10. Dynamic force analysis using force polygon method

Topic 6 (Rattan)

Belts and chains

1. Belt drives

2. Open-belt and crossed-belt drives

3. Action of belts on pulleys

4. Velocity ratio and slip

5. Materials for belts

6. Types of pulleys and crowning

7. Law of belting

8. Length of belt

9. Ratio of friction tensions and power transmitted

10. Centrifugal effect and maximum power transmitted

11. Chains – length, angular speed ratio and classification

Topic 7

Gears

1. Common types of toothed gears

2. Terms and definitions

3. Fundamental law of toothed gearing

4. Involute tooth gearing

5. Sizing of involute gear tooth

6. Backlash and antibacklash gears

7. Contact ratio

8. Interference and undercutting of gear teeth

9. Cycloidal tooth gearing

Topic 8

Gear Trains

1. Speed ratio

2. Classification of gear trains

3. Ordinary gear trains

4. Planetary gear trains

5. Tabular analysis of planetary gear trains

6. Kinematic analysis of multiple-stage planetary gear trains

7. Differentials

8. Reactions torques and relations in gearboxes

Topic 9

Cams

1. Disc Cam mechanism nomenclature

2. Pressure Angle

3. The displacement diagrams

4. Types of follower motions

5. Graphical constructions of follower displacement diagrams for given motions

6. Comparison of follower motions

7. Graphical construction of Disc Cam Profile

Topic 10

Flywheels 

1. Introduction

2. Mathematical Formulation

3. Turning moment diagram

4. Determination of size of flywheels

5. Branched Systems

Topic 11 (Rattan)

Balancing

1. Static and Dynamic balancing

2. Transfer of a force from one plane to the another

3. Balancing of several masses in different planes

4. Force balancing of linkages

5. Balancing of reciprocating mass

Topic 12 (Rattan)

Vibrations

1. Types of vibrations

2. Basic features of vibrating systems

3. Free longitudinal vibrations

4. Damped vibrations

5. Forced Vibrations

6. Forced-Damped vibrations

7. Magnification factor

8. Vibration isolation and transmissibility

9. Forcing due to unbalance and support motion

10. Uniformly loaded shaft

11. Shaft carrying several loads

12. Whirling of shafts

13. Unit Review

Software/Hardware Used

Software

• Software: MechAnalyser
• Version: 5
• Instructions: Free download: http://www.roboanalyzer.com/mechanalyzer.html
• Additional resources or files: N/A

Hardware

• N/A

Unit Changes Based on Student Feedback