Question

Explain different types of strain.

Answer 1

Hint: There are three types of strain namely normal or longitudinal strain, shearing strain and volumetric or bulk strain which have been categorized on the basis of type of distortion produced by them. Although all of them define some kind of distortion but they are quite different from each other.

Complete answer:
The three types of strain are as follows:
1.Normal strain or longitudinal strain: Normal strain is the ratio of change in length of a body to the original length of the body. It is also known as longitudinal strain because it is concerned with the change in length of the body and its original length. Mathematically it can be expressed as:
${{\text{S}}_{1}}=\dfrac{\Delta L}{L}$
2.Shearing strain: Shearing strain as defined as the angular distortion produced in the body which means that it is the ratio of the displacement of the surface of the body and the height of the body, but remember that the surface of the body is the one on which the stress is acting. Mathematically it can be expressed as:
${{\text{S}}_{2}}=\dfrac{l}{h}$
3.Volumetric strain or bulk strain: Volumetric strain is the ratio of the change in volume of a body and its original volume. It is also known as bulk strain because it considers the whole volume of the body. Mathematically it can be expressed as:
${{\text{S}}_{3}}=\dfrac{\Delta V}{V}$

Note:
Strain is the deformation produced in a body when stress is applied to it. As explained above, strain is the change is length, angle and volume of a body. But remember that strain is only produced when an external force is applied on the body, no strain will be developed due to internal forces.