Page 13 - Marks Calculation for Machine Design

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FOREWORD

Once the design and components of a machine have been selected there is an important
engineering analysis process the machine designer should perform to verify the integrity of
the design. That is what this book is about.
The purpose of Marks’ Calculations for Machine Design is to uncover the mystery
behind the principles, and particularly the formulas, used in machine design. All too often
a formula found in the best of references is presented without the necessary background
for the designer to understand how it was developed. This can be frustrating because of
a lack of clarity as to what assumptions have been made in the formula’s development.
Typically, few if any examples are presented to illustrate the application of the formula with
appropriate units. While these references are invaluable this companion book presents the
application.
In Marks’ Calculations for Machine Design the necessary background for every ma-
chine design formula presented is provided. The mathematical details of the development
of a particular design formula have been provided only if the development enlightens and
illuminates the fundamental principles for the machine designer. If the details of the devel-
opment are only a mathematical exercise, they have been omitted. For example, in Chapter 9
the steps involved in the development of the design formulas for helical springs are pre-
sented in great detail since valuable insight is obtained about the true nature of the loading
on such springs and because algebra is the only mathematics needed in the steps. On the
other hand, in Chapter 3 the formulas for the tangential and radial stresses in a high-speed
rotating thin disk are presented without their mathematical development since they derive
from the simultaneous integration of two differential equations and the application of ap-
propriate boundary conditions. No formula is presented unless it is used in one or more of
the numerous examples provided or used in the development of another design formula.
Why has this approach been taken? Because a formula that remains a mystery is a
formula unused, and a formula unused is an opportunity missed—forever.
It is hoped that Marks’ Calculations for Machine Design will provide a level of comfort
and confidence in the principles and formulas of machine design that ultimately produces
a successful and safe design, and a proud designer.

THOMAS H. BROWN,JR., PH.D., P.E.

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