Mechanical System DesignSemester VII - Mechanical Engineering(Pune University)

R. B. PatilM.E. (Mech) (Design Engg.)

Head, Department of Mechanical Engineering,Army Institute of Technology,Pune.

Mechanical System DesignR. B. Patil(Semester VII – Mechanical Engineering, Pune University)

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First Printed in India : July 2006Second Edition : October 2007Third Revised Edition : July 2008Fourth Revised Edition : August 2009Reprint : August 2010

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Scope of the Book…

UNIT - 1

Design of Cylinders and Pressure Vessels :

Thick and thin cylinders - Thin cylindrical and spherical vessels - Lame's equation - Clavarino’s

and Birnie’s equations - Design of hydraulic and pneumatic cylinders - Autofrettage and

compound cylinders - Gasketed joints in cylindrical vessels - Modes of failures in pressure vessels

- Unfired pressure vessels - Classification of pressure vessels as per I. S. 2825 - Categories and

types of welded joints - Weld joint efficiency - Corrosion, erosion and protection vessels - Stresses

induced in pressure vessels - Materials of construction - Thickness of cylindrical and spherical

shells - Design of end closures as per code - Nozzles and Openings in pressure vessels -

Reinforcement of openings in shell and end closures - Area compensation method - Types of

vessel supports. (Refer Chapter 2)

UNIT - 2

Optimum Design :

Objectives of optimum design - Johnson's Method of Optimum Design (MOD) - Adequate and

optimum design - Primary, subsidiary and limit equations - Optimum design with normal and

redundant specifications of simple machine elements like : tension bar, transmission shaft, helical

spring. (Refer Chapter 3)

UNIT – 3

Design of Flywheel :

Design of flywheel - Fundamental equation of motion - Torque analysis - Disk and rimmed

flywheels - Stresses in flywheel rim and spokes - Design of disc and rimmed flywheels for various

applications - Standard dimensions of flywheels. (Refer Chapter 1)

UNIT - 4

Statistical Consideration in Design :

Frequency distribution - Histogram and frequency polygon - Normal distribution - Units of

measurement of central tendency and dispersion - Standard variable - Population combinations -

Design and natural tolerances - Design of assembly - Statistical analysis of tolerances -

Mechanical reliability and factor of safety. (Refer Chapter 4)

Design for Manufacture :

General principles of design for manufacture and assembly (DFM and DFA) - Principles of design

of castings and forgings - Design for machining - Design for powder metallurgy - Design for

welding. (Refer Chapter 8)

UNIT - 5

Design of Gear Boxes for Machine Tool Applications :

Basic considerations in design of drives - Determination of variable speed range - Graphical

representation of speed and structure diagram - Deviation diagram - Ray diagram - Selection of

optimum ray diagram - Difference between number of teeth of successive gears in a change gear

box - Analysis of twelve speed gear box – Compound ray diagram. (Refer Chapter 5)

Aesthetic and Ergonomic Considerations in Design of Products :

Basic types of product forms - Designing for appearance - Shape, features, materials, finishes,

proportions, symmetry, contrast etc. - Morgan's colour code - Ergonomic considerations - Relation

between man, machine and environmental factors - Design of displays and controls - Practical

examples of products or equipments using ergonomic and aesthetic design principles.

(Refer Chapter 7)

UNIT - 6

Design of Material Handling Systems :

System concept - Basic principles, Objectives of material handling system - Unit load and

containerization.

Belt conveyors :

Flat belt and troughed belt conveyors - Capacity of conveyor - Rubber covered and fabric ply belts

- Belt tensions - Conveyor pulleys - Belt idlers - Tension take-up systems - Power requirement of

horizontal belt conveyors for frictional resistance of idlers and pulleys. (Refer Chapter 6)

Preface

It gives a great pleasure to present this book on ‘Mechanical System Design’. This book has been written for the third course in ‘Machine Design’, especially for the final year students of mechanical engineering. This is the third book of the series on ‘Machine Design’, which comprehensively covers the design of different mechanical systems and various aspects of system design, used in engineering applications. The main objective of this book is to bridge the gap between the reference books written by the renowned international authors and the requirements of undergraduate students.

The book has been presented in a simple language without compromising the quality of text. The concepts have been developed from the fundamentals. The main emphasis has been given on explaining the concepts rather than merely providing the information. Every concept is illustrated with the help of number of solved examples, which are arranged in the order of increasing degree of difficulty. The list of formulae has been given at the end of each chapter for the ready reference. This book is an outcome of the years of classroom interaction with the students.

I would like to express my thanks to Shri. Sachin Shah and Shri Pradeep Lunawat of ‘Tech-Max Publications’ for their efforts in publishing this book. My thanks are due to all those people who have directly or indirectly contributed to this book.

Last, but not least, my special thanks go to all my students whose continuous feedback while teaching this subject is the source of inspiration behind this book.

A feedback in the form of suggestions and comments from the readers for further improvement of the book will be highly appreciated.

1st October 2007 - R.B. Patil

To My

Daughter Neha

&

Son Nikhil

- Author