Characteristics of stress

Stress, what is it? A scalar or a vector quantity. Since stress equals the internal reaction force divided by the cross-sectional area, none corresponds to it because it’s a tensor quantity.

This article will teach the definition of stress and study all its characteristics and types. The factors on which it depends and principles. Discussion of all of this with perfect real-life examples. 

What is Stress?

The restoring force per unit area is defined as stress. When we apply an external force to the body to modify its form, the body responds by creating a reversing force.

Let’s see a real-life example to understand the meaning of stress:

When two external forces are applied simultaneously to a rubber ball, the ball produces a force that acts in the opposite direction.

The ball is subjected to the opposing force of the restoring force due to an external force. The magnitude of this force is the same as the external force.

Formula of Stress

To calculate stress, use the formula below: 

Stress =force/ Cross-sectional area

σ= F/A

Where, 

σ= stress, F is force and A is area

Units of stress= N/m² or Pascals (Pa)

Normal Stress = Axial Force / Cross-sectional Area

Longitudinal Stress = Deforming force / Cross-sectional Area

Volume Stress = Force / Area 

Shearing Stress = Force / Surface Area

Types of Stress

In Physics, there are a total of 8 types of stress, but it mainly focuses on the two: Normal Stress and Tangential stress (also known as Shearing stress).

Normal Stress

The normal force is created when an axial force is applied to an object. This means that there is perpendicular stress applied to the body. Objects’ stress levels return to normal when their length and volume are changed.

Longitudinal Stress

Longitudinal stress is created when an equal and opposing force is applied to two cross-sectional sections of the cylinder. The cylinder will bend throughout its length as a result. The length of the body varies with longitudinal stress. As a result, the diameter of the hole changes somewhat. It is divided into two groups based on the direction. There are two types of stress: tensile and compressive.

Volume Stress

Volume stress is also referred to as bulk stress. An example of volume stress is when the body’s volume shifts under stress. Tangential stress, or volume stress, changes the body’s shape, whereas normal stress changes the length or volume of the body. 

Shearing Stress

Shearing stress is a force applied uniformly across the surface area. Surfaces are said to be tangent when the forces acting on them are parallel, and the stress acting on them traces a tangent. Typically, shearing stress is the result of such tension.

Tensile stress

When an object expands due to an applied force or deformation, it is called tensile stress. An example would be to stretch a rod or wire by applying equal and opposite forces (outwards) at both ends.

Compression stress

In the event of tangential force, a body’s shape and volume change. In response to a compression load, the length of the body is reduced. Tensile and compression stress are opposing forces. When you squeeze a pet’s squeak toy in your hand, you produce compression to tension.

Hydraulic stress

Hydraulic stress refers to the internal force per unit area acting on liquids. When a fluid exerts a force on the body, hydraulic stress is the restoring force per unit area. The distinction between stress and pressure is that stress analyses internal force per unit area, and pressure examines outward force per unit area. Hydraulic stress is defined similarly in the case of liquids.

Radial stress

Suppose the outside surface of a thick-walled cylinder has zeros and the interior surface has a gauge pressure equal to and opposite to the outside surface pressure. Radial stress is neglected in practice since circumferential and longitudinal strains outweigh radial stress.

Conclusion

Firstly remember and understand the meaning of stress, its formula and its causes. Understand all the characteristics and types of Stress. Then the difference between all stress. You solve some example problems or previous years’ questions based on the formula to get more clarity. Remember all the SI and CGS units of stress and also the derivation.

Here’s a short example of the cause of stress on rocks or earth’s crust surfaces.

An applied force that causes a rock to distort is stress. Stresses at plate boundaries include compression at convergent boundaries, tension at divergent boundaries, and shear at transform boundaries.