Stress Formula

Stress Formula:

Stress is defined as a quantity that describes the magnitude of forces that cause deformation. Stress is as force per unit area.

When force pulls an object and causes its elongation like the stretching of an elastic band, that stress is a tensile stress.

When forces cause a compression of an object, that is a compressive stress. 

When an object is squeezed from all sides, like a submarine in the depths of an ocean, this is called  stress, a bulk stress (or volume stress). In other kinds of situations, the acting forces may be neither tensile nor compressive, and still produce a noticeable deformation. 

For example, assume that you hold a book tightly between the palms of your hands, then with one hand you press-and-pull on the front cover away from you, while with the other hand you do the same with the back cover towards you. In that case, when deforming forces act tangentially to the  surface of the object, we call them ‘shear’ forces and the stress they cause is called “shear stress.

Stress = elastic modulus  × strain

Stress= F / A

Where

F =Force applied

A =Area on that force is acting

The SI unit of stress is called the pascal (Pa). When one newton force presses on a unit surface area of one meter squared, therefore stress is one pascal.

The measure of an external force acting over the cross sectional area of an object is stress. Stress has units of force per area: N/m² (SI). The SI units are commonly referred to as Pascals and  abbreviated as Pa.

In every material the stress the size of each portion is different and the elastic deformity is linear.

Solved examples:

1. Find the stress if a force of 40 N is acting on an area of  4mm²?

Given: Force F = 40 N,

Area A = 4 mm²

Stress=  F / A

=40/4× 10^-6

=10×10⁶ N/m²  

2. An elastic spring is given a force of 2000 N over an area of 0.1 m2. Calculate the stress?

Given that F = 2000 N,

A = 0.1 m²

Stress=  F / A

=2000/0.1

=20000 N/m²