stress
Whenever some external system of forces acts on a body, it undergoes some deformation the body undergoes some deformation, it sets up some resistance to the deformation. This resistance per unit area to deformation, is called stress.
strain
When a system of forces act on a body, it undergoes some deformation. This deformation per unit length is called as unit strain or simply a strain.
Mathematically
Strain = (Change in Length)/(Original Length)
Primary Strain or Linear Strain The deformation of the bar, per unit length in the direction of the force is known as primary or linear strain.
Secondary Strain or Lateral Strain Every direct stress is always accompanied by a strain in its own direction, and an opposite kind of strain in every direction, at right angles to it. Such strain is known as secondary or lateral strain.
no unit
Strain is the deformation of a material from stress. Strain is simply a ratio of the change in length to the original length. Deformations that are applied perpendicular to the cross section are normal strains, while deformations applied parallel to the cross section are shear strains.
There is no unit for strain.
compressive stress, compressive strain
Compressive Stress:-When a body is subjected to two equal and opposite axial pushes P ( also called compressive load), then the stress induced at any section of the body is known as compressive stress.
Compressive Strain:- When a body is subjected to two equal and opposite axial pushes P ( also called compressive load), there will be an increase in cross-sectional area and a decrease in length of the body. The ratio of the decrease in length to the original length is known as compressive strain.
shear stress, shear strain
When a body is subjected to two equal and opposite forces, acting tangentially across the resisting section, as a result of which the body tends to shear off across the section, the stress and strain induced is shear stress and shear strain.
