When the thin cylinder is subjected to the internal pressure as we have already calculated that there is a change in the cylinder dimensions i.e, longitudinal strain and hoop strains come into picture. As a result of which there will be change in capacity of the cylinder or there is a change in the volume of the cylinder hence it becomes imperative to determine the change in volume or the volumetric strain.
The capacity of a cylinder is defined as
V = Area X Length
= πd2/4 x L
Let there be a change in dimensions occurs, when the thin cylinder is subjected to an internal pressure.
(i) The diameter d changes to → d δ d
(ii) The length L changes to → L δ L
Therefore, the change in volume = Final volume − Original volume
Therefore to find but the increase in capacity or volume, multiply the volumetric strain by original volume.
Change in Capacity / Volume or