Volumetric Strain (e_v)

When body is subjected to external forces, there will be change in volume. The ratio of change in volume to the original volume called as "Volumetric Strain".
And it denoted by e_v.

∴ e_v = ^{Change in Volume} / _{Original Volume}
∴ e_v = ^δV / _V
Where,
             δV - change in volume,
             V - Original volume.
Volumetric strain is algebraic sum of all axial or linear strains.
∴ e_v = e_x + e_y + e_z
Where,
             e_x - Strain in X-direction,
             e_y - Strain in y-direction,
             e_z - Strain in z-direction.