When the force P applied at a bar, it just causes elongation at section x-x. A force of similar value to the force P will be created / exists in a bar in the opposite direction to prevent them getting it will be in equilibrium. The forces that exist at section x-x is said to be uniformly distributed over the entire cross-section and it is known as stress.
Units for stress is N/m2 @ Pascal (Pa), where the unit force is Newton (N) and unit area is m2.
The normal stresses can be broken down into two types of tensile stress and compressive stress, which distinguish both direction of the internal forces. Tensile stress (Figure 5.1) occurs when the internal forces are in tension or in the direction out of the material. Conventions of the tensile stress is positive (+ ve). Meanwhile, the compressive stresses (Figure 5.2) is the opposite, that the internal forces in compression or in the direction into the material. Signs of the compressive stress is negative (-ve).
The normal stresses can be broken down into two types of tensile stress and compressive stress, which distinguish both direction of the internal forces. Tensile stress (Figure 5.1) occurs when the internal forces are in tension or in the direction out of the material. Conventions of the tensile stress is positive (+ ve). Meanwhile, the compressive stresses (Figure 5.2) is the opposite, that the internal forces in compression or in the direction into the material. Signs of the compressive stress is negative (-ve).
