# Young’s Modulus

The young’s modulus is a numerical constant, named for the English physician (Thomas Young) of the 18th century. This modulus is used for describing the elastic properties of the soil undergoing the compression or tension in only one direction such as the metal rod that is returned to its original length after being compressed or stretched. ## Importance of Young’s Modulus

The Young’s modulus of the materials is the fundamental property of each material that cannot be subjected to any change. It is greatly dependent on pressure and temperature. This modulus is the essence of the stiffness of the materials, in other words, it is used to measure how easily the material can be stretched or bent. This modulus is of significant importance for the scientists and doctors as this constant can tell that when a specific structural implant will be deformed.

This modulus is used to measure the ability of the material to withstand the changes in its length when it is subjected to the lengthwise compression or tension. Sometimes, this modulus is also referred to as modulus of elasticity and it is equal to the longitudinal stress divided by the strain.

## The Equation and Units of Young’s Modulus

For Young’s modulus, the equation is as follows.

E = σ / ε = (F/A) / (ΔL/L0) = FL0 / AΔL

Here E is Young’s modulus, which is expressed in the Pascals (Pa) usually. σ is used to represent the uniaxial stress. Here the ε denotes the strain. F is used for the force of extension or compression. A is used to represent the cross-sectional surface area or the cross-section that is perpendicular to the applied force. Δ L represents the change in length that is positive during the stretched conditions and is negative under the compression. The original length is represented by the L0. Whereas, Pa is an SI unit for Young’s modulus. Most often its values are expressed in the terms of megapascals (MPa), gigapascals (GPa), Newton per Square Millimeter (N/mm2), or Kilonewtons per square millimeter (KN/mm2). Usually, its English unit is pounds per square inch (PSI), or mega PSI (Mpsi).

## Modulus of Elasticity

The literal meaning of modulus is to measure. Here the multiple expressions are used for measuring the elasticity and is also called modulus of elasticity. The Young’s modulus is used for describing the tensile elasticity along with the line when there is the application of the opposing forces. It is the ratio between the tensile strain and the tensile stress.