Stress

Quick
Stress, similar to pressure, is the internal resistance to an applied force. Stresses have units of force per area. There are two main types of stress: normal stress and shear stress. Stress may also be represented by the letter S. Stress is a very wide area of study, with many associated concepts and principles. There are many different kinds of stresses used in many areas of engineering.

Equations
(Eq1)
stress =
 P A
General equation for stress

Nomenclature
 P load A area

Types of Stress Quicklist
 Bearing Bending Bulk Compressive Contact Engineering
 Fluctuating Hertzian Hoop Hydraulic Nominal
 Normal Plane Principal Residual Shaft
 Shear Tensile Thermal True Volume Von Mises

Details

Physics may define stress differently than in engineering under mechanics of materials. On one hand, three types of stress are defined: tension, compression, and shear. Tension is stretching due to forces acting at the ends of a member. Compression is when a member is being squeezed from all sides by the force of water pressure. Shear occurs such as when a shaft is being twisted by forces at its ends that cause torques about its axis. Therefore, stress characterizes the strength of the forces causing the stretch, squeeze, or twist, usually on a "force per unit area" basis. Another type of stress is hydraulic stress, which is the stress experienced by an object submerged in a fluid, with pressure being applied on the object from the fluid, in which case the object is compressed uniformly on all sides.

Stress characterizes the strength of the forces causing the stretch, squeeze, or twist. Tension is associated with stretching, compression with squeezing, and shear with twisting. The general equation for stress is:

(Eq1)
stress =
 P A

In the study of engineering, there is also something called strength. For more information see the lesson: Difference Between Stress and Strength. Also, there is true stress, and engineering stress. For more information see the lesson: True Stress, True Strain, Engineering Stress, and Engineering Strain

Related
▪ L - Difference Between Stress and Strength
▪ L - True Stress, True Strain, Engineering Stress, and Engineering Strain
▪ L - Stresses on an Oblique Plane Under Axial Loading
▪ L - Average Normal Stress in Solid Member
▪ L - Stresses In A Shaft
▪ L - Transformation of Plane Stress
▪ L - Principle Stresses and Maximum Shear Stress
▪ P - Normal and Shearing Stresses for an Axial Force