This book consists of statics, kinematics, kinetics, and mechanics of materials.The main contents of the book include: statics of a particle and of a rigid body, friction,kinematics of a particle and of a rigid body in plane motion, resultant motion of aparticle, kinetics of a particle and of a rigid body in plane motion, mechanicalproperties of materials, axial tension and compression of bars, torsion of shafts,bending of beams, stress analysis and theories of strength, combined loadings, andstability of columns.
The book can be used as an English, Chinese, or bilingual textbook of engineeringmechanics for the student majoring in aeronautical, mechanical, civil, and hydraulicengineering.
《工程力学》由静力学、运动学、动力学和材料力学组成。主要内容包括:质点静力学和刚体静力学、摩擦、质点运动学和刚体平面运动学、质点合成运动、质点动力学和刚体平面动力学、材料机械性能、杆的轴向拉伸与压缩、轴的扭转、梁的弯曲、应力分析与强度理论、组合载荷和压杆稳定。
《工程力学》可作为高等院校航空、机械、土木和水利等学科专业学生的英文、中文或双语工程力学教材。
目錄:
Preface
前言
English Edition
Chapter 1 Fundamental Concepts of Theoretical Mechanics
1.1 What Is Theoretical Mechanics
1.2 Basic Concepts
1.3 General Principles
Chapter 2 Statics of Particle
2.1 System of Concurrent Forces
2.2 Resultant of Coplanar Concurrent Forces
2.3 Equilibrium of Coplanar Concurrent Forces
2.4 Resultant of Spatial Concurrent Forces
2.5 Equilibrium of Spatial Concurrent Forces
Problems
Chapter 3 Reduction of Force System
3.1 Moment of Force about Point
3.2 Moment of Force about Given Axis
3.3 Principle of Moments
3.4 Components of Moment of Force about Point
3.5 Moment of Couple
3.6 Resultant of Couples
3.7 Equivalence of Force Acting on Rigid Body
3.8 Reduction of Force System
Problems
Chapter 4 Statics of Rigid Body
4.1 Equilibrium of Rigid Body
4.2 Equilibrium of Two-Dimensional Rigid Body
4.3 Two-Force and Three-Force Bodies
4.4 Planar Trusses
4.5 Equilibrium of Three-Dimensional Rigid Body
Problems
Chapter 5 Friction
5.1 Types of Friction
5.2 Sliding Friction
5.3 Angles of Friction
5.4 Problems Involving Sliding Friction
5.5 Rolling Resistance
Problems
Chapter 6 Kinematics of Particle
6.1 Motion of Particle
6.2 Motion of Particle Represented by Vector
6.3 Motion of Particle Represented by Rectangular Coordinates
6.4 Motion of Particle Represented by Natural Coordinates
Problems
Chapter 7 Kinematics of Rigid Body in Plane Motion
7.1 Plane Motion of Rigid Body
7.2 Translation
7.3 Rotation about Fixed Axis
7.4 General Plane Motion
Problems
Chapter 8 Resultant Motion of Particle
8.1 Motion of Particle
8.2 Rates of Change of Vector
8.3 Resultant of Velocities
8.4 Resultant of Accelerations
Problems
Chapter 9 Kinetics of Particle
9.1 Newton?s Second Law of Motion
9.2 Equations of Motion of Particle
9.3 Method of Inertia Force for Particle in Motion
9.4 Method of Work and Energy for Particle in Motion
9.5 Method of Impulse and Momentum for Particle in Motion
Problems
Chapter 10 Kinetics of Rigid Body in Plane Motion
10.1 Motion for System of Particles
10.2 Motion of Mass Center of System of Particles
10.3 Motion of System of Particles about Its Mass Center
10.4 Equations of Motion for Rigid Body in Plane Motion
10.5 Method of Inertia Force for Rigid Body in Plane Motion
10.6 Method of Work and Energy for Rigid Body in Plane Motion
10.7 Method of Impulse and Momentum for Rigid Body in Plane Motion
Problems
Chapter 11 Fundamental Concepts of Mechanics of Materials
11.1 What Is Mechanics of Materials
11.2 Basic Assumptions of Materials
11.3 External Forces
11.4 Internal Forces
11.5 Stresses
11.6 Strains
11.7 Deformations of Members
Problems
Chapter 12 Mechanical Properties of Materials
12.1 Tensile or Compressive Test
12.2 Tension of Low-Carbon Steel
12.3 Ductile and Brittle Materials
12.4 Stress-Strain Curve of Ductile Materials without Distinct Yield Point
12.5 Percent Elongation and Percent Reduction in Area
12.6 Hooke?s Law
12.7 Mechanical Properties of Materials in Compression
Chapter 13 Axial Tension and Compression of Bars
13.1 Definition of Axial Tension and Compression
13.2 Axial Force
13.3 Normal Stress on Cross Section
13.4 Saint-Venant?s Principle
13.5 Normal and Shearing Stresses on Oblique Section
13.6 Normal Strain
13.7 Deformation of Axially Loaded Bar
13.8 Statically Indeterminate Axially Loaded Bar
13.9 Design of Axially Loaded Bar
13.10 Stress Concentrations
Problems
Chapter 14 Torsion of Shafts
14.1 Definition of Torsion
14.2 Twisting Moment
14.3 Hooke?s Law in Shear
14.4 Shearing Stress on Cross Section of Circular Shaft
14.5 Normal and Shearing Stresses on Oblique Section of Circular Shaft
14.6 Angle of Twist
14.7 Statically Indeterminate Circular Shaft
14.8 Design of Circular Shaft
Problems
Chapter 15 Shearing Force and Bending Moment of Beams
15.1 Definition of Bending
15.2 Shearing-Force and Bending-Moment Diagrams
15.3 Relations between Distributed Load, Shearing Force, and Bending Moment
15.4 Relations between Concentrated Load, Shearing Force, and Bending Moment
Problems
Chapter 16 Normal Stress and Shearing Stress in Beams
16.1 Types of Bending
16.2 Normal Stresses on Cross Section in Pure Bending
16.3 Normal and Shearing Stresses on Cross Section in Transverse-Force Bending
16.4 Design of Prismatic Beams in Bending
Problems
Chapter 17 Deflection and Slope of Beams
17.1 Deformation of Beams
17.2 Method of Integration
17.3 Method of Superposition
17.4 Statically Indeterminate Beams
Problems
Chapter 18 Stress Analysis and Theories of Strength
18.1 State of Stress
18.2 Transformation of Plane Stress
18.3 Principal Stresses for Plane Stress
18.4 Maximum Shearing Stress for Plane Stress
18.5 Stresses in Pressure Vessels
18.6 Generalized Hooke?s Law
18.7 Theories of Strength under Plane Stress
Problems
Chapter 19 Combined Loadings
19.1 Definition of Combined Loadings
19.2 Stress in Bar Subject to Eccentric Tension or Compression
19.3 Stress in I-Section Beam Subject to Transverse-Force Bending
19.4 Stress in Beam Subject to Bending and Axial TensionCompression
19.5 Stress in Shaft Subject to Torsion and Bending
Problems
Chapter 20 Stability of Columns
20.1 Definition of Buckling
20.2 Critical Load of Long Slender Columns under Centric Loadwith Pin Supports
20.3 Critical Load of Long Slender Columns under Centric Load with Other Supports
20.4 Critical Stress of Long Slender Columns under Centric Load
20.5 Critical Stress of Intermediate Length Columns under Centric Load
20.6 Design of Columns under Centric Load
Problems
References
Appendix Ⅰ Centers of Gravity and Centroids
Ⅰ.1 Center of Gravity and Centroid of Plate
Ⅰ.2 Center of Gravity and Centroid of Composite Plate
Ⅰ.3 Center of Gravity and Centroid of 3D Body
Ⅰ.4 Center of Gravity and Centroid of 3D Composite Body
Appendix Ⅱ Mass Moments of Inertia
Ⅱ.1 Moment of Inertia and Radius of Gyration
Ⅱ.2 Parallel-Axis Theorem
Appendix Ⅲ Geometrical Properties of Areas
Ⅲ.1 First Moment and Centroid
Ⅲ.2 First Moment and Centroid of Composite Area
Ⅲ.3 Moment of Inertia and Polar Moment of Inertia
Ⅲ.4 Radius of Gyration and Polar Radius of Gyration
Ⅲ.5 Product of Inertia
Ⅲ.6 Parallel-Axis Theorem
Ⅲ.7 Moment of Inertia and Polar Moment of Inertia of Commonly-Used Areas
Appendix Ⅳ Geometrical Properties of Rolled-Steel Shapes
Ⅳ.1 I Steel
Ⅳ.2 Channel Steel
Ⅳ.3 Equal Angle Steel
Ⅳ.4 Unequal Angle Steel
Appendix Ⅴ Deflections and Slopes of Beams
中文版
第1章 理论力学的基本概念
1.1 什么是理论力学
1.2 基本概念
1.3 普遍原理
第2章 质点静力学
2.1 汇交力系
2.2 平面汇交力的合成
2.3 平面汇交力的平衡
2.4 空间汇交力的合成
2.5 空间汇交力的平衡
习题
第3章 力系的简化
3.1 力对点之矩
3.2 力对轴之矩
3.3 力矩定理
3.4 力对点之矩的分量
3.5 力偶矩
3.6 力偶的合成
3.7 作用于刚体上力的等效
3.8 力系的简化
习题
第4章 刚体静力学
4.1 刚体平衡
4.2 二维刚体的平衡
4.3 二力和三力物体
4.4 平面桁架
4.5 三维刚体的平衡
习题
第5章 摩擦
5.1 摩擦分类
5.2 滑动摩擦
5.3 摩擦角
5.4 含有滑动摩擦的问题
5.5 滚动摩阻
习题
第6章 质点运动学
6.1 质点的运动
6.2 质点运动的矢量表示
6.3 质点运动的直角坐标表示
6.4 质点运动的自然坐标表示
习题
第7章 刚体平面运动学
7.1 刚体平面运动
7.2 平移
7.3 定轴转动
7.4 一般平面运动
习题
第8章 质点合成运动
8.1 质点的运动
8.2 矢量的变化率
8.3 速度的合成
8.4 加速度的合成
习题
第9章 质点动力学
9.1 牛顿第二运动定律
9.2 质点运动方程
9.3 运动质点的惯性力法
9.4 运动质点的功-能法
9.5 运动质点的冲量-动量法
习题
第10章 刚体平面动力学
10.1 质点系的运动
10.2 质点系质心的运动
10.3 质点系相对质心的运动
10.4 平面运动刚体的运动方程
10.5 平面运动刚体的惯性力法
10.6 平面运动刚体的功-能法
10.7 平面运动刚体的冲量-动量法
习题
第11章 材料力学的基本概念
11.1 什么是材料力学
11.2 材料的基本假设
11.3 外力
11.4 内力
11.5 应力
11.6 应变
11.7 构件的变形
习题
第12章 材料机械性能
12.1 拉伸或压缩试验
12.2 低碳钢拉伸
12.3 塑性和脆性材料
12.4 没有明显屈服点的塑性材料的应力-应变曲线
12.5 伸长率和断面收缩率
12.6 胡克定律
12.7 材料压缩机械性能
第13章 杆的轴向拉伸与压缩
13.1 轴向拉伸与压缩的定义
13.2 轴力
13.3 横截面上的正应力
13.4 圣维南原理
13.5 斜截面上的正应力和剪应力
13.6 线应变
13.7 轴向加载杆的变形
13.8 静不定轴向加载杆
13.9 轴向加载杆的设计
13.10 应力集中
习题
第14章 轴的扭转
14.1 扭转的定义
14.2 扭矩
14.3 剪切胡克定律
14.4 圆轴横截面上的剪应力
14.5 圆轴斜截面上的正应力和剪应力
14.6 扭转角
14.7 静不定圆轴
14.8 圆轴的设计
习题
第15章 梁的剪力与弯矩
15.1 弯曲的定义
15.2 剪力和弯矩图
15.3 分布载荷、剪力和弯矩之间的关系
15.4 集中载荷、剪力和弯矩之间的关系
习题
第16章 梁的正应力与剪应力
16.1 弯曲的类型
16.2 纯弯曲梁横截面上的正应力
16.3 横力弯曲梁横截面上的正应力和剪应力
16.4 等截面弯曲梁的设计
习题
第17章 梁的挠度与转角
17.1 梁的变形
17.2 积分法
17.3 叠加法
17.4 静不定梁
习题
第18章 应力分析与强度理论
18.1 应力状态
18.2 平面应力状态变换
18.3 平面应力状态的主应力
18.4 平面应力状态的最大剪应力
18.5 压力容器中的应力
18.6 广义胡克定律
18.7 平面应力状态强度理论
习题
第19章 组合载荷
19.1 组合载荷的定义
19.2 偏心拉伸或压缩杆的应力
19.3 横力弯曲工字梁的应力
19.4 弯曲与拉压梁的应力
19.5 扭转与弯曲轴的应力
习题
第20章 压杆稳定
20.1 失稳的定义
20.2 两端铰支中心加载细长压杆的临界载荷
20.3 其他支撑中心加载细长压杆的临界载荷
20.4 中心加载细长压杆的临界应力
20.5 中心加载中长压杆的临界应力
20.6 中心加载压杆的设计
习题
参考文献
附录Ⅰ 重心与形心
Ⅰ.1 薄板的重心与形心
Ⅰ.2 组合薄板的重心与形心
Ⅰ.3 三维物体的重心与形心
Ⅰ.4 三维组合物体的重心与形心
附录Ⅱ 转动惯量
Ⅱ.1 转动惯量与回转半径
Ⅱ.2 平行移轴定理
附录Ⅲ 截面几何性质
Ⅲ.1 静矩与形心
Ⅲ.2 组合截面的静矩与形心
Ⅲ.3 惯性矩与极惯性矩
Ⅲ.4 惯性半径与极惯性半径
Ⅲ.5 惯性积
Ⅲ.6 平行移轴定理
Ⅲ.7 常用截面的惯性矩与极惯性矩
附录Ⅳ 型钢几何性质
Ⅳ.1 工字钢
Ⅳ.2 槽钢
Ⅳ.3 等边角钢
Ⅳ.4 不等边角钢
附录Ⅴ 常用梁的挠度与转角
內容試閱:
Chapter 1 Fundamental Concepts of Theoretical
Mechanics
1.1 What Is Theoretical Mechanics
Engineering mechanics is the science that applies the principles of mechanics to the
analysis and design of engineering structures and machines. It usually includes theoretical
mechanics and mechanics of materials.
Theoretical mechanics is the study of equilibrium or motion of bodies subjected to the
action of forces, and consists of statics, kinematics and dynamics. Statics is the study of bodies
at rest or in equilibrium; kinematics treats the geometry of the motion without regard to the
forces acting on bodies; and kinetics deals with the relation between the motion of bodies and
the forces acting on bodies.
In theoretical mechanics, bodies are assumed to be perfectly rigid. Though actual
structures and machines are never absolutely rigid and deform under the action of forces, these
deformations are usually small and do not affect the state of equilibrium or motion of the
structures and machines under consideration.
1.2 Basic Concepts
1. Length
Length is used to locate the position of a point in space. The position of a point can be
defined by three lengths measured from a certain reference point in three given directions.
2. Time
Time is used to represent a nonspatial continuum in which events occur in irreversible
succession from the past through the present to the future. To define an event, it is not
sufficient to indicate its position in space. The time of the event should be given.
3. Mass
Mass is used to characterize the quantity of matter that a body contains. The mass of a
body is not dependent on gravity and therefore is different from but proportional to its weight.
Two bodies of the same mass, for example, will be attracted by the earth in the same manner;
they will also offer the same resistance to a change in velocity.
4. Force
Force is used to represent the action of one body on another. A force tends to produce an
acceleration of a body in the direction of its application. The effect of a force is completely
characterized by its magnitude, direction, and point of application.
5. Particle
If the size and shape of a body do not affect the solution of the specific problem under
consideration, then this body can be idealized as a particle, i.e., a particle has a mass, but its
size and shape can be neglected. For example, the size and shape of the earth is insignificant
compared to the size and shape of its orbit, and therefore the earth can be modeled as a particle
when studying the orbital motion of the earth.
6. Rigid Body
A rigid body can be considered as a combination of a large number of particles in which
all the particles occupy fixed positions with respect to each other within the body both before
and after the action of forces, i.e., a rigid body is defined as one which does not deform when
it is subjected to the action of forces.
7. Scalars
Scalars possess only magnitude, e.g., length, time, mass, work, energy. Scalars are added
by algebraic methods.
8. Vectors
Vectors possess both magnitude and direction direction is understood to includes both
the inclination angle that the line of action makes with a given reference line and the sense of
the vector along the line of action, e.g., force, displacement, impulse, momentum. Vectors are
added by the parallelogram law.
9. Free Vectors
A free vector can be moved anywhere in space provided it remains the same magnitude
and direction.
10. Sliding or Slip Vectors
A sliding or slip vector can be moved to any point along its line of action.
11. Fixed or Bound Vectors
A fixed or bound vector must remain at the same point of application.
1.3 General Principles
1. Parallelogram Law
This law states that two forces acting on a particle can be replaced by a single resultant
force obtained by drawing the diagonal of the parallelogram which has sides equal to the given
forces.
For example, two forces 1
F and 2
F acting on a particle O, Fig. 1.1a, can be replaced
by a single force R , Fig. 1.1b, which has the same effect on the particle O and is called the
resultant force of the forces 1
F and 2
F . The resultant force R can be obtained by drawing
a parallelogram using 1
F and 2
F as two adjacent sides of the parallelogram. The diagonal
that passes through O represents the resultant force R , i.e., 1 2
R=F+F . This method for
finding the resultant force of two forces is known as the parallelogram law.
From the parallelogram law, an alternative method for determining the resultant force of
two forces by drawing a triangle, Fig. 1.2b, can be obtained. The resultant force R of the
forces 1
F and 2
F can be found by arranging 1
F and 2
F in tip-to-tail fashion and then
connecting the tail of 1
F with the tip of 2
F , i.e., 1 2
R=F+F . This is known as the triangle
rule.
2. Principle of Transmissibility
This principle states that the state of equilibrium or motion of a rigid body will remain
unchanged if one force acting at a given point of the rigid body is replaced by another force of
the same magnitude and same direction, but acting at a different point, provided that the two
forces have the same line of action.
For example, a force F , Fig. 1.3a, acting on a given point O of a rigid body can be
replaced by a force ′ F , Fig. 1.3b, of the same magnitude and same direction, but acting at a
different point O′ on the same line of action. The two forces F and ′ F have the same
effect on the rigid body and are said to be equivalent. This principle shows that the effect of a
force on a rigid body remains unchanged provided the force acting on the rigid body is moved
along its line of action. Thus forces acting on a rigid body are sliding vectors.
replaced by a force ′ F , Fig. 1.3b, of the same magnitude and same direction, but acting at a
different point O′ on the same line of action. The two forces F and ′ F have the same
effect on the rigid body and are said to be equivalent. This principle shows that the effect of a
force on a rigid body remains unchanged provided the force acting on the rigid body is moved
along its line of action. Thus forces acting on a rigid body are sliding vectors.
where F is the force of gravitation between the two particles, G is the universal constant
of gravitation, 1
m and 2
m are, respectively, the mass of each of the two particles, and r is
the distance between the two particles.
When a particle is located on or near the surface of the earth, the force exerted by the
earth on the particle is defined as the weight of the particle. Taking 1
m equal to the mass M
of the earth, 2
m equal to the mass m of the particle, and r equal to the radius R of the
earth, and letting
2
M
g G
R
= 1.3
where g is the acceleration of gravity, then the magnitude of the weight of the particle can be
given by
W =mg 1.4
The value of g is approximately equal to 9.81 ms
2
in SI units, as long as the particle is
located on or near the surface of the earth.
Chapter 2 Statics of Particle
2.1 System of Concurrent Forces
A body under consideration can be idealized as a particle if its size and shape are able to
be neglected. All the forces acting on this particle can be assumed to be applied at the same
point and will thus form a system of concurrent forces.
2.2 Resultant of Coplanar Concurrent Forces
A coplanar system of concurrent forces consists of concurrent forces that lie in one plane.
1. Graphical Method for Resultant of Forces
The resultant force of a coplanar system of concurrent forces acting on a particle can be
obtained by using the graphical method. If a particle is acted upon by three or more coplanar
concurrent forces, the resultant force can be obtained by the repeated applications of the triangle rule.
Considering that a particle O is acted upon by coplanar concurrent forces 1
F , 2
F , and 3
F ,
Fig. 2.1a, the resultant force R of these forces can be obtained graphically by arranging all
the given forces in tip-to-tail fashion and connecting the tail of the first force with the tip of the
last one, Fig. 2.1b. This method is known as the polygon rule.
We thus conclude that a coplanar system of concurrent forces acting on a particle can be
replaced by a resultant force through the concurrence, and that the resultant force is equal to
the vector sum of the given coplanar concurrent forces, i.e.,
Example 2.1
Two rods, AC and AD, are attached at A to column AB, Fig. E2.1a. Knowing that the