Types Of Elastic Constants

The study of solids is a very vast field and has great significance in science. Therefore, it is very important to study the stiffness and the stability of solids while studying any solid material. This calculation of the degree of stability and stiffness of the solids can easily be calculated with the help of elastic constants. Now, it is very important to know what an elastic constant is. So, according to Hooke’s law, the measurement of the relationship between stress and strain in a crystal can be easily done with the help of elastic constants. There are four different types of elastic constants, and it is very easy to define different types of elastic constants.

Significance Of Elastic Constants

Elastic constants have a great significance. These constants are used to define the major properties of a material which are generally solids that undergo the effect of factors like stress, strain, deformation, and reformation to their initial situation.  With the help of different types of elastic constants, the mechanical properties of a material can be studied very easily. They are clearly and directly used to assess elastic strains or energy in materials under stress from various sources, including external, internal, thermal, and so on.

Define Different Types Of Elastic Constants 

Generally, there are four types of elastic constants, and it is necessary to define different types of elastic constants. These different types of elastic constants are stated as follows –

• Bulk Modulus – Also called volume modulus of elasticity, bulk modulus states that within the elastic limits of a body, the ratio of direct stress to corresponding volumetric strain is shown to be constant when subjected to mutually perpendicular direct stresses that are identical and equal. The bulk modulus is a ratio symbolised by the letter “K.” Mpa is the unit of the bulk modulus.

            Bulk modulus(K)= direct stress/ volumetric stress

• Rigidity Modulus – The shear modulus or rigidity modulus states that when a body is subjected to shear stress, it changes shape; the ratio of shear stress to corresponding shear strain is known as the rigidity modulus or modulus of rigidity. The letters “G” or “C” or “N” are used to represent it. Mpa is the unit of stiffness modulus.

Modulus of Rigidity= shear stress/ shear strain 

• Young’s Modulus – Also known as the modulus of elasticity,  states that when a body is subjected to tensile or compressive stress, the stress imparted is directly proportional to the strain within the elastic limits of that body according to Hooke’s law. Young’s modulus, often known as the modulus of elasticity, is the constant ratio of applied stress to strain. The letter “E” stands for Young’s modulus. The megapascal unit of elasticity is the same as the megapascal unit of stress (Mpa). 1 N/mm2 is equal to 1 Mpa.

       Young’s modulus= stress/ strain 

• Poisson’s Ratio – When simple tensile stress is applied to a body within its elastic limits, the dimensions of the body change in both the direction of the load and the opposite direction. Longitudinal and lateral strain is calculated by dividing these modified dimensions by their original dimensions. Poisson’s ratio is the proportion of lateral strain to longitudinal strain. The symbol “µ” is used to denote it. The highest Poisson ratio for an ideal elastic incompressible material is 0.5. The Poisson’s ratio for most engineering materials is between 0.25 and 0.33. It doesn’t have any units.

Poisson’s Ratio= lateral strain/ longitudinal strain 

Hooke’s Statement On Elastic Constants

According to Hooke’s law, when a material is loaded within its elastic limit, the stress produced is proportional to the stress produced by the stress. This means that the ratio of stress to corresponding strain within the elastic limit is constant. An elastic modulus is the unit of measurement of an object’s or substance’s obstruction or force to be deformed elastically. One can also say non-permanently when a force or stress is applied. The elastic modulus is defined as the slope of its stress-strain curve in the elastic deformation region. A stiffer material will have a higher elastic modulus.

Here, stress is the force causing the deformation divided by the area the force is applied, and strain is the ratio of the change in some parameter caused by the deformation to the parameter’s original value.

Conclusion

From the data mentioned above, we can conclude that the different elastic constants have a great significance. The study of the behaviour of a material cannot be done with the help of these constants. Young’s modulus. Rigidity modulus, Poisson’s Ratio, and bulk modulus analyse the stability and stiffness of materials very easily and precisely. Moreover, the field where these different types of elastic constants are used is vast. This is because it can be used to determine the stretchability of material and storage of potential energy due to the stretch.