Hello friends,
Hope you are doing well. In our last lecture we have studied
about stress and strain. We have learnt about basic concept behind it. Strain
is a measurement quantity which is ratio of change in length to original length under loading condition. But when we stretch a body, its dimensions
changes in all directions. According to it strain can be divided into two
types. There are many other factors on which we can categorized strain. So today we will
learn about types of strain. Hope you like it.
Let’s starts with its types.
Types of strain:
Strain can be categorized into following aspects.
According to the direction of loading:
Let’s try to learn with example. Take a rubber piece of L length, and B width. Apply a pull load on its two parallel faces along its length
and observe it. The length of the rubber piece slightly increases,
suppose it is ∆L. We also observed some little change in the width and height as
they both decrease slightly. Suppose change in width is ∆B and change in height is ∆W.
So we have observed three value of change in length in all three
direction. According to it strain can be divided into two types.
Lateral Strain:
The ratio of change in length to its original length in the
perpendicular direction of the loading is called lateral strain. In the above
example it can be represented by
Longitudinal Strain:
The ratio of change in length to its original length in the
direction of loading is known as longitudinal strain. In the above example longitudinal
strain can be represent by.
According to the loading:
According to the types of loading strain can be divided into three types.
Normal strain:
It can further divided into two types.
Compressive strain:
Strain measure under compressive loading is known as
compressive strain. It tends to increase the cross section area and decrease
the length of the body.
Tensile Strain:
Strain measure under tensile loading is known as tensile
strain. It tends to decrease the cross section and increase the length of the
body.
Shear Strain:
When the shear stress is applied on a body, it tends to
deform the shape of the body as shown in the figure. The change in tangential
angle in the direction of the loading is called shear strain.
Volumetric strain:
The ratio of change in volume to original volume under normal
loading condition is known as volumetric strain.
This is all about types of strain. If you have any query
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