Elastic Constants – Young’s Modulus, Modulus of Rigidity and Bulk Modulus

In this article, you will learn about the Elastic Constant – Young’s modulus, Modulus of rigidity, and Bulk modulus. We will also discuss the difference between Young’s modulus, Modulus of rigidity, and Bulk modulus.

The various elastic constants in the strength of materials are

Young’s modulus or modulus of elasticity

Modulus of rigidity or Shear Modulus
Bulk Modulus

Let’s discuss them one by one

Young’s Modulus

Definition: It is defined as the ratio of tensile stress or compressive stress to the corresponding strain within the elastic limit. It is denoted by the symbol E. It is also known as the modulus of elasticity or elastic modulus.

Where

E = Young’s Modulus

σ = Tensile or compressive stress

e = Tensile or compressive strain

The SI unit of Young’s modulus is N/mm²
.

Modulus of Rigidity

Definition: It is defined as the ratio of shear stress to corresponding shear strain within the elastic limit. It is also known as shear modulus. It is represented by C or G or N.

Where

τ = Shear stress

ɸ = Shear strain

The SI unit of C is N/mm²

Bulk Modulus

Definition: It is defined as the ratio of direct stress to the corresponding volumetric strain within the elastic limit. It is denoted by K.

σ = Direct stress

(dV/V) = Volumetric strain

The SI unit of C is N/mm²

Difference Between Young’s Modulus, Modulus of Rigidity, and Bulk Modulus.

S.no	Young’s Modulus	Modulus of Rigidity	Bulk Modulus
1.	It is the ratio of tensile or compressive stress to the corresponding strain within elastic limit.	It is the ratio of shear stress to the corresponding shear strain within elastic limit.	It is the ratio of direct stress to the corresponding volumetric strain within elastic limit.
2.	It is denoted by E.	It is denoted by C or G or N.	It is denoted by K.
3.	E = stress/ strain	C = shear stress/shear strain	K = direct stress/ volumetric strain.

This is all about the Elastic constant – Young’s modulus, modulus of Rigidity, and Bulk modulus. And if you found this article informative and useful then don’t forget to like and share it.