CIE 113:
MECHANICS OF
DEFORMABLE
BODIES
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COMMONLY USED SI UNITS
QUANTITY NAME SI
SYMBOL
Energy Joule J (1J = 1N.m)
Force Newton N (1N = 1kg.m/
Length meter m
Mass kilogram kg
Moment (Torque) Newton.meter N.m
Plane Angle radian rad
Rotational Frequency revolution/second r/s
Stress (Pressure) Pascal Pa (1 Pa = 1 N/ )
Temperature degree celcius
Time second s
Power watt w ( 1 w = 1 J/s)
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COMMONLY USED SI UNITS
MULTIPLYING FACTORS PREFIX SYMBOL
1X Giga G
1X Mega M
1X Kilo k
1X millimeter mm
1X micro µ
1X nano n
1 ft = 12 inches ksi - kilo lb/
1m = 1000 mm kips – kilo lbs
1kg = 9.81 N psi - lb/
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Mechanics of Deformable Bodies is
going to focus more on bodies that
are "deformable". To put it simply,
deformable bodies are bodies that
will not retain its shape/ form when
a force is applied onto it.
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Mechanics of Deformable Bodies is
going to focus more on bodies that
are "deformable". To put it simply,
deformable bodies are bodies that
will not retain its shape/ form when
a force is applied onto it.
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FORCES THAT CAUSE DEFORMATION
A normal force is a type of force applied
NORMAL FORCE PERPENDICULAR to a cross-sectional area of
the body.
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FORCES THAT CAUSE DEFORMATION
TWISTING This tends to twist, rotate the cross-sectional
MOMENT/TORQUE area of the body being considered.
BENDING MOMENT
When this forces act on a body, they generate stress.
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NORMAL STRESS Stress developed under the action of the forces acting axially or
perpendicular to the resisting area, also known as normal stress.
TWO TYPES:
𝑃
𝜎= 1. TENSILE STRESS, - tends
𝐴 to elongate the material.
P = Force ( N, KN, lb)
A = Area (
2. COMPRESSIVE STRESS, –
tends to shorten the
material.
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SHEAR STRESS This stress arises whenever the applied loads cause one section
of a body to slide past its adjacent section.
Three TYPES:
τ 1. Single
Shear
P = Force ( N, KN, lb)
A = Area (
2. Double
Shear
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3. Punching
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SHEAR STRESS – SINGLE SHEAR
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SHEAR STRESS – DOUBLE SHEAR
Shearing
occurs
Shearing
occurs
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