SLIDE 1
SMU 2113 ENGINEERING SCIENCE PART 1 Introduction to Mechanics of Materials and Structures
These slides are designed based on the content of this reference textbook.
SLIDE 2 To introduce basic principles of the mechanics of materials and structures. To illustrate the applications of mechanics of materials for structural members subjected to simple loading conditions.
OBJECTIVES
At the end of PART 1, students should be able to:
- calculate deformation, strains and stresses of a structural
member subjected to simple loading, namely axial, direct shear, torsion and bending.
- identify the various mechanical properties of common
engineering materials.
- analyze elastic deflection of a beam.
SLIDE 3
A branch of mechanics that studies the relationships between external loads applied to a deformable body and the intensity of internal forces acting within the body.
Mechanics of Materials
SLIDE 4 Stress Strain Equilibrium of forces Mechanical properties of materials
Axial force Torsion Bending Numerous examples/ applications
SCOPE
SLIDE 5
Typical Engineering Structures
Applications involving combined loading
SLIDE 6
Equilibrium of a deformable body
A particle or body is in equilibrium provided it is at rest if originally at rest or has a constant velocity if originally in motion. Types of external loads
SLIDE 7 Equilibrium of a deformable body
Equations for equilibrium of forces and moments are employed to determine support reactions
kN A M
y B
75 . 18 ;
kN B F
y y
75 . 33 ;
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Concept of stress
Strained Element
General loading conditions
SLIDE 11 Concept of stress
Normal stress The intensity of force acting normal to A
A Fz
A z
lim A Fx
A zx
lim A Fy
A zy
lim
Shear stress The intensity of force acting tangent to A
SLIDE 12 Direct normal stress
Average normal stress
A P
z
SLIDE 13
Applications
Examples of structures under direct tensile stress Tie rod Cable
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Applications
Examples of structures under direct compressive stress
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SLIDE 19 Average shear stress
Shear stress is the stress component that acts in the plane
A V
avg
V is the internal resultant shear force at the section (V = P/2) Average shear stress
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Applications
Lap joint Single-shear connection
SLIDE 25
Applications
Lap joint Double-shear connection
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SLIDE 29
Concept of strain
Strain is used to describe the deformation of a body by changes in length of line segments and the changes in the angles between them After straining
SLIDE 30 Normal strain
Normal strain is the elongation or contraction
- f a line segment per unit of length
s s s
avg
Average normal strain
s
s 1
SLIDE 31
Normal strain
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SLIDE 33 Shear strain
Shear strain is the change in angle that occurs between two line segments that were originally perpendicular to one another
t along A C n along A B nt
lim 2
Shear strain at point A
SLIDE 34
Shear strain
SLIDE 35
