Eng Ahmed Y Manama Eng Saeed A Shurab Eng Ahmed Al Afeefy Objectives Measure the shear deformation of the block Determine of modulus of rigidity Introduction Rubber blocks in shear force are often used on engine and in equipment mounting to isolate vibrations They do this by ID: 559479
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Slide1
Exp.4: Rubber in Shear Apparatus
Eng.
Ahmed Y Manama
Eng.
Saeed
A
Shurab
Eng. Ahmed Al
AfeefySlide2
Objectives
Measure the shear deformation of the block.
Determine of modulus of rigidity.Slide3
Introduction
Rubber blocks in shear force are often used on engine and in equipment mounting to isolate vibrations. They do this by absorbing shock energy by deforming. This deformation leads to a decrease in cross-section as the block lengthens, an effect described by Poisson's Ratio.Slide4
Introduction
Shear
Stress and
StrainSlide5
Introduction
The
force F
acting
at angle theta with respect to the horizontal , the force resolved to it’s component ( perpendicular and parallel to the surface area).
The perpendicular component will produce an Axial
Stress
The parallel component will effect the rod by producing a Shear
Stress.
The
units of both Axial and Shear Stress will normally be
lb
/in
2
or N/m
2Slide6
Introduction
Shear
Strain
The shear stress produces a displacement of the rod which produces a shear strain. The edge of the rod is displaced a horizontal distance, from its initial position ,this displacement (or horizontal deformation) divided by the length of the rod L is equal to the Shear Strain. Slide7
IntroductionSlide8
Introduction
Tan γ = γ = δ / L
Where :
δ
is the deformation
γ
shear strain
L
original length
The shear strain is dimensionless.Slide9
Shear Modulus (Modulus of Rigidity)
The modulus of rigidity ( shear modulus) (denoted by G or sometimes S or μ,) is concerned with the deformation of a solid when it experiences a force parallel to one of its surfaces while its opposite face experiences an opposing force (such as friction
).
Shear modulus is usually measured in
GPa
or
ksi
(thousands of pounds per square.Slide10
Shear Modulus (Modulus of Rigidity)
It’s defined as the ratio of
shear stress
to the
shear strain:
where
F
is the force which acts
A
is the area on which the force acts
Δx
is the transverse displacementI is the initial lengthSlide11
Equipment
A rubber block 150 x 75 x 25mm is bonded to two aluminum alloy plates.Slide12
Results
Load
(N)
Dial Gauge
(mm)
Deflection
(mm)
0
10
20
30
40
50
60
70
80
90
100
110
120