When we apply a force on a body it will undergo deformation
and its length will increase or decrease. Length increases
when the force is tensile and decreases when the force
applied is compressive.
The
ratio of Change in dimension to the original dimension is
called strain.
Strain
= ε = Change in dimension/original dimension
There
are two types of strains.
1.
Normal strain (Tensile, compressive and volumetric)
2.
Shear strain
Normal
strain:
It can
be divided into three types.
a.
Tensile strain:
When we
apply a tensile force on a body its length increases. The
ratio of increase in length to the original length.
Tensile
strain = ε_{t} = L – L_{0 }/ L
Where L
= Original length
L_{0}
= new length
b.
Compressive strain:
When we
apply a compressive force on a body its length decreases.
The ratio of decrease in length to the original length is
called compressive strain.
Compressive strain = ε_{c} = L – L_{0 }/ L
Where L
= Original length
L_{0}
= new length
c.
Volumetric strain:
When we
apply a force on all sides of a body its volume will
decrease. The ratio of change in volume to the original
volume is called volumetric strain.
Volumetric strain = ε_{v} = V – V_{0 }/ V
Where V
= Original volume
V_{0}
= new volume
Shear
Strain:
When we apply a tangential force on a body there is an
angular displacement (θ), which measures the shear strain.
Shear
strain = tan θ
