Bulk Strain
The change in the volume to original volume (V) is called
bulk strain.
Note: It is obvious from
the above definition of Strain, that Strain is just a number without a unit.
Stress
The measure of resistance to deformation is called stress.
The following stresses corresponding to each type of deformation can be defined.
Longitudinal or Tensile Stress
The restoring forces per unit normal crosssectional area is
called the tensile stress.
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Shear Stress
The restoring force, per unit lateral area, is called shear stress.
Bulk Stress
The restoring force per unit normal area of the surface is called bulk stress.
Since Pressure = Force / Normal Area
Note : The stress is measured in the unit of Newton/(meter)^{2} i.e., N/m^{2}.
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