MECHANICS I
STATICS++
JAMES W DALLY AND ROBERT J
BONENBERGER
UNIVERSITY OF MARYLAND AT
COLLEGE PARK
The
predecessor to this textbook "Design Analysis of Structural Elements"
was prepared to support an integrated course offering for Statics and Mechanics
of Materials. However most
engineering programs in the U. S. offer these two topics as separate courses.
To better align the material content of "Design Analysis of
Structural Elements" with the sequence of course offerings, we have divided
its content into the two classical subjects—Mechanics I: Statics++ and
Mechanics II: Mechanics of Materials. In
separating the content we have retained some elements of integration of the two
subjects. The content of the
Mechanics I textbook includes methods for determining stresses and strains in
uniaxial members and a discussion of material properties and material behavior.
For this reason Mechanics I has the subtitle Statics ++.
The Statics course provides the first exposure of engineering students to the
study of mechanics. While Statics is
a relatively simple subject, many students find it difficult, and they often
perform far below our expectations. In
an effort to improve the curriculum, several members of the faculty at the
University of Maryland have been working for more than a decade to enhance the
student’s learning experience when studying these first two courses in
mechanics. These books indicate some
of the changes in the philosophy adopted by the faculty when presenting the
subject matter traditionally offered in introductory mechanics courses.
MECHANICS I
STATICS ++
JAMES W. DALLY
ROBERT J. BONENBERGER, JR.
University of Maryland, College Park
The
changes in the philosophy were based on five premises:
-
Present the
fundamental concepts in a more interesting manner.
·
Change the approach to make it more realistic and less abstract.
·
Couple the mechanics content tightly to design.
-
Provide
a smooth transition from Introduction to Engineering Design (ENES 100) to
Mechanics I (ENES 102).
·
Incorporate a hands-on experience including design, construction and
testing of a model of a construction project.
·
Provide the analysis methods and the scaling relations for verifying the
safety of the design of this model.
-
Emphasize
modeling structural components by stressing throughout the text the
importance of preparing a complete free body diagram (FBD).
·
Show the method for constructing complete FBDs.
·
Integrate the FBD with the application of the equilibrium equations.
·
Approach the solution of equilibrium problems with equilibrium relations
based on force and moment components.
·
Introduce vectors in conjunction with forces and moments, but only
employ vector analysis after both FBDs and equilibrium concepts have been firmly
established.
4.
Include
early concepts from Mechanics of Materials into the content of Statics.
·
The concepts of normal and shearing stresses are introduced early in
Statics.
5.
Emphasize
the design of uniaxial components for safety.
·
Stress is compared to strength to give safety factors for components.
·
Behavior of engineering materials is introduced and physical properties
such as strength and modulus of elasticity are described.
·
Sizing of structural components for safety and cost are demonstrated.
These textbooks have a relatively long history.
We began developing notes for the first edition of Design Analysis of
Structural Elements with a pilot offering in the spring semester of 1999.
Many revisions were made before a limited first edition of the textbook
was published in the summer of 1999. The
second edition was published in 2000 and was used by about a thousand students.
The third edition, written in 2001, included six new chapters to expand
the coverage necessary for a complete Mechanics of Materials course.
The fourth edition of Design Analysis of Structural Elements, published
in 2004, was similar to the third edition except for reorganization and changes
of the homework problems. Since that
time the about 4,500 students have studied mechanics with the previous editions
of these books.
DEDICATION
ABOUT
THE AUTHORS
PREFACE
CONTENTS
CHAPTER
1 BASIC CONCEPTS IN MECHANICS
1.1 Introduction
1.2
Statics and Mechanics of Materials
1.3
History of Mechanics
1.4
Newton’s Laws of Motion
1.5
Forces
1.6
Basic Quantities and Units
1.7
Conversion of Units
1.8
Significant Figures
1.9
Scalars, Vectors and Tensors
1.10
Summary
References
Problems
CHAPTER
2 FORCES AND MOMENTS
2.1 Introduction
2.2
Internal and External Forces
2.3
Force Vectors
2.4
Adding and Subtracting Vectors
2.5
Components of a Force Vector
2.6
Concurrent and Coplanar Forces
2.7
Space Forces
2.8
Moments
2.9
Vector Mechanics
2.10 Summary
Problems
CHAPTER
3 FREE BODY DIAGRAMS AND EQUILIBRIUM
3.1 Introduction
3.2
Equations of Equilibrium
3.3
Free Body Diagrams (FBDS)
3.4
Solving for Reactions
3.5
Forces in Cable and Pulley Arrangements
3.6
Forces in Springs
3.7
FBDS of Partial Bodies
3.8
Solving for Internal Forces
3.9
Summary
Problems
CHAPTER
4 AXIALLY LOADED STRUCTURAL MEMBERS
4.1 Introduction
4.2
Normal Stress, Strains and Deformation
4.3
Shear Stresses
4.4
Bearing Stresses
4.5 The Tensile Test
4.6 Material Properties
4.7 True Stress and True
Strain
4.8 Summary
References
Problems
CHAPTER
5 AXIALLY LOADED STRUCTURAL MEMBERS
5.1 Introduction
5.2 Design
Analysis of Wire, Rods and Bars
5.3 Stresses
on Oblique Planes
5.4 Axial
Loading of a Stepped Bar
5.5 Axial
Loading of a Tapered Bar
5.6 Scale
Models
5.7 Summary
Problems
CHAPTER 6 TRUSSES
6.1 Introduction
6.2 Method of Joints
6.3 Zero
Force Members
6.4 Method
of Sections
6.5 Summary
Problems
CHAPTER
7 FRAMES AND MACHINES
7.1 Introduction
7.2 Frames—Examples
7.3 Machines—Examples
7.4 Construction
Equipment
7.5 Summary
Problems
CHAPTER
8 SPACE STRUCTURES AND 3-D EQUILIBRIUM
8.1 Introduction
8.2 Solutions
Using Trigonometric Analysis
8.3 Solutions
using Vector Mechanics
8.4 Three
Dimensional Equilibrium
8.5 Summary
References
Problems
CHAPTER
9 FRICTION
9.1 Introduction
9.2 Static
and Dynamic Friction
9.3 Measuring
the Coefficient of Friction
9.4 Friction
and Stability
9.5 Friction Effects on Wedges
9.6 Friction Effects on Screws
9.7 Summary
References
Problems
Chapter
10 PROPERTIES OF AREAS
10.1 Area
10.2 First
Moment of an Area
10.3 Centroid
of the Area A
10.4 Locating
the Centroid of a Composite Area
10.5 Second
Moment of an Area
10.6 The Parallel Axis Theorem
10.7 Moments
of Inertia of Composite Areas
10.8 Summary
Problems
APPENDICES
APPENDIX
A Wire and Sheet Metal Gages
APPENDIX
B1 Physical Properties of Common
Structural Materials
APPENDIX
B2 Tensile Properties of Common
Structural Materials
APPENDIX
B3 Tensile Properties of Non
Metallic Materials
APPENDIX
C Design Projects
C.1 Bridges
C.2 Structural
Systems in Large Buildings
C.3 Construction
Cranes
C.4 Communication
Towers
INDEX
TO
ORDER
