Conditions of Equilibrium
VM211: STATICS AND MECHANICS
INTRODUCTION &
CHAPTER 4: EQUILIBRIUM OF A RIGID BODY
Dr. Shane Johnson
=0
0 =0
A rigid body will remain in equilibrium provided the sum of all the external
forces about a point is equal to zero and
VM211: STATICS AND MECHANICS
CHAPTER 4: EQUILIBRIUM OF A RIGID BODY
TOPICS:
(1) EQUILIBRIUM IN 3D & BOUNDARY CONDITIONS
(2) FRICTION & IMPENDING MOTION
Instructor: Yongxing Shen
How should we model
the supports at A, B,
and C?
How about other
forces?
Draw
VM211: STATICS AND MECHANICS
CHAPTER 5: STRUCTURAL ANALYSIS
TRUSSES, METHOD OF JOINTS & SECTIONS
Instructor: Yongxing Shen
Pending from last time.
The coefficients of static and kinetic friction between the drum and brake bar are
= 0.4 and = 0.3 respecti
VM211: STATICS AND MECHANICS
INTRODUCTION &
CHAPTER 1: GENERAL PRINCIPLES
CHAPTER 2: FORCE VECTORS
Instructor: Yongxing Shen
What is this course about?
Mechanics: the study between the state of a body in motion
or at rest and applied forces
- Rigid-body
VM211: INTRODUCTION TO SOLID MECHANICS
CHAPTER 8: STRESS AND STRAIN
Instructor: Yongxing Shen
Contents
Normal and shear stresses
Normal and shear strainswhere we start to examine deformable
bodies
Page 2
Normal and Shear Stresses
Normal Stress
= lim
0
VM211: STATICS AND MECHANICS
CHAPTER 7: INTERNAL LOADINGS
Instructor: Yongxing Shen
Motivation
The design of any structural or mechanical member requires
an investigation of the loading acting within the member in
order to be sure the material can resist
VM211: STATICS AND MECHANICS
CHAPTER 4: EQUILIBRIUM OF A RIGID BODY
TOPICS:
FRICTION & IMPENDING MOTION
Instructor: Yongxing Shen
Friction
During contact with other bodies
Force of resistance acting on body
Force directed opposite to possible or existing
VM211: STATICS AND MECHANICS
CHAPTER 6: GEOMETRIC PROPERTIES AND
DISTRIBUTED LOADINGS
(SECTIONS 6.1-6.4)
Instructor: Yongxing Shen
Reducing a force and couple system to a single resultant force
(revisited, see Sec. 3.9)
Such a single resultant force exist
VM211: STATICS AND MECHANICS
CHAPTER 5: STRUCTURAL ANALYSIS
TRUSSES, METHOD OF JOINTS & SECTIONS
Instructor: Yongxing Shen
Determine the force in member CF.
Page 2
Determine the force in member EB.
Page 3
Frames and machines
Frames: stationary, used to su
VM211:
CHAPTER 3: FORCE SYSTEM RESULTANTS
Dr. Shane Johnson
Moment Resultant
=
= ( )
1
Force Couple
Cross Product
= = ( sin )
=
=
=
Page 7
=
For element :
For element :
= ( )
For element :
Moment of a force - Vector Formulation
= ( )
Page 8
VM211:
CHAPTER 3: FORCE SYSTEM RESULTANTS
Instructor: Yongxing Shen
Main topics
Moment of a force
- Concept
- How to calculate
Moment of a couple
Resultants of nonconcurrent force systems
How to reduce a simple distributed loading to a
resultant force hav