**Introduction:**

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.

**Description:**

The capacity of a cylinder is defined as

**V = Area X Length
= πd ^{2}/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.

Hence

Change in Capacity / Volume or