STRESS AND STRAIN- DIRECT, NORMAL OR AXIAL STRESS

STRESS can be represented by symbol.

Normal stress results from a uniformly or equally applied direct force across a cross section. This definition is illustrated in figure below:

The load P causes the cylinder to increase in length. At equilibrium, the internal force P will be produced at a cross-section x-x as shown in figure above. The stress may be compressive or tensile depending on the nature of the internal forces and are measured in units of newton per square metre.

Normally, tensile stress is taken as positive value while compressive stress is negative value.