Now stress is defined as the force intensity or force per unit area. Here we use a symbol s
to represent the stress.
Where A is the area of the X – section
Here we are using an assumption that the total force or total load carried by the
rectangular bar is uniformly distributed over its cross – section.
But the stress distributions may be for from uniform, with local regions of high stress
known as stress concentrations.
If the force carried by a component is not uniformly distributed over its cross – sectional
area, A, we must consider a small area, „dA' which carries a small load dP, of the total
force „P', Then definition of stress is
As a particular stress generally holds true only at a point, therefore it is defined
The basic units of stress in S.I units i.e. (International system) are N / m (or Pa)