What is Strain in Physics? | Definition, Formulas, Symbols, Types – Elasticity

Strain Definition in Physics:
1. The fractional change in configuration is called strain.

2. A strain is the response of a system to an applied stress. When a material is loaded with a force, it produces a stress, which then causes a material to deform.

We are giving a detailed and clear sheet on all Physics Notes that are very useful to understand the Basic Physics Concepts.

What is Strain in Physics? | Definition, Formulas, Symbols, Types – Elasticity

Strain Formula:

Strain = \(\frac{\text { Change in configuration }}{\text { Original configuration }}\)

It has no unit and it is a dimensionless quantity.

Types of Strain in Physics:
According to the change in configuration, the strain is of three types:

  • Longitudinal strain
  • Volumetric strain
  • Shearing strain

(i) Longitudinal strain Definition:
A longitudinal strain is defined as. Change in the length to the original length of an object. It is caused due to longitudinal stress and is denoted by the Greek letter epsilon ε.

Longitudinal strain Formula:

Longitudinal strain = \(\frac{\text { Change in length }}{\text { Original length }}\)
ε = \(\frac{ΔL}{L}\)

ε = Longitudinal strain
ΔL = Change in length
L = Original length

(ii) Volumetric strain Definition:
A Volumetric strain is defined as The volumetric strain is the unit change in volume, i.e. the change in volume divided by the original volume. volumetric strain is denoted by εvol.

Volumetric strain Formula:

Volumetric strain = \(\frac{\text { Change in volume }}{\text { Original volume }}\)
εvol = \(\frac{ΔV}{V}\)

εvol = Volumetric strain
ΔV = Change in volume
V = Original volume

(iii) Shear strain Definition:
1. Shearing strain is measured as a change in angle between lines that were originally perpendicular.

2. Shear strain is the ratio of displacement to an object’s original dimensions due to stress, and is the amount of deformation perpendicular to a given line rather than parallel to it.

Shearing strain = Angular displacement of the plane perpendicular to the fixed surface.

Shear Strain Symbol:
γ or ε

The Shear Strain Formula:

S = \(\frac{Δx}{X}\)

S = Shear Strain
Δx = change in dimension
X = original dimension

Elasticity defines a property of an object that has the ability to regain its original shape after being stretched or compressed. Learn about the deforming force applied on an elastic object and how the stress and strain works on an object. What is a Hooke’s law and how it is applicable for the concept of elasticity.

Deforming Force Elasticity
Stress Strain
Hooke’s Law Elastic Modulus
Types of Modulus of Elasticity Poisson’s Ratio
Stress and Strain Curve Thermal Stress
Cantilever Beam Torsion of a Cylinder