Strain

Strain:  The measure of deformation in the body is known as strain.

For an example, if a bar is subjected to a direct load and hence a stress, the bar will change in length (L) and change in length by an amount ( ), the strain produced is defined as,

Thus, strain is measure of deformation of material, it is non-dimensional ( it has not unit ). It is simply a ratio of two quantities with the same unit.

Types of strain:

       1.      Tensile strain 

       2.      Compressive strain

       3.      Shear strain

       4.      Volumetric strain

1) Tensile Strain:  If the change in dimension is due to tensile stress which means increase in length than the ratio of increase of length to the original length is called tensile strain.

1)  Compressive Strain: If the change in dimension is due to compressive stress which means the ratio of decreases of length to the original length is known as compressive strain.

2)  Shear stress : If the change in dimension is due to shear stress which means the angle through which a body is distorted than this angle is known as shear strain.

4)  Volumetric strain : Volumetric  strain is the ratio of change volume to the original volume of the   body is known as volumetric strain.



#Credit:Prof. Dr. Md. Iqbal Mahmud   
Dept.of Textile Engineering, MBSTU