Stress strain measurement or Stress-Strain analysis is an important part of advanced physical science and engineering. The study of Stress and strain plays a vital role in science application too. This discipline uses several techniques or methods to figure out strains and stresses on different objects.

The analysis of stress and strain is essential in aerospace engineering, mechanical engineering and civil engineering. And if you are also interested in knowing more about Stress-Strain analysis and management keep reading. Here, in this article, we will discuss some major factors of stress and strain measurements.

What Is Stress? What You You Need To Know

Stress Strain Measurement

Before you move towards the Stress strain measurement let us know about stress and strain one by one briefly. Stress is known as the amount of force applied to a specific material area per unit. The formula for stress is defined as

Stress = applied Force/cross-sectional area of the object
Σ = F/A
Here, Σ is the stress
F is the applied force
And A is the cross-section area of any specific object or material.
The scientific symbol of Stress is S. And the measurement unit of stress is Pa or Nm2. 

What Is Strain? What You You Need To Know

Strain is another important part of Stress strain measurement. Where stress is defined as the ratio of applied Force amount per unit area. Strain is the ratio of extension per unit length.
Strain = extension /natural length of the object

Types of Strain

There are primarily two types of Stress strain measurement among which one is known as Tensile strain and the second is comprehensive strain.

  • Comprehensive strain – The change in the length of the object or material due to comprehensive strain is called Comprehensive strain.
  • Tensile strain – The changed length of any object or material due to Tensile is called Tensile strain.

Stress And Strain: The Importance of Understanding The Relationship

To understand Stress strain measurement you also need to know about the relationship between stress and strain. Stress and strain have a straight and consistent relationship that lasts up to the stretchable limitation. The relationship breaks which leads to the physical distortion of the object, after the material crosses its yield point.

Hooke’s law

The English scientist Robert Hooke of the 19th century defined the relationship between stress and strain very finely. When he was working with elasticity and springs, he discovered many different materials have similar or same features when their stress and strain contain is analysed closely.
According to Hooke’s law, the amount of strain on a specific material is the same as the amount of applied force on the material which must be within the stretching point (yield point) of the material.

Young Modulus

Stress Strain Measurement

If you pick stress against strain Instead of drawing a strain graph for an object to showcase its elasticity, you will get a straight line.
E = stress /strain = σ / ε
It is because the amount of strain is always proportionate to the amount of stress. And the E here represents stiffness. And does not change for any object.
E = σ / ε
And,  σ = F/A
Therefore, E = F/A ε and ε = e / lo so I / ε = lo / e
So, E = F lo / A ε


Stress strain measurement or Stress-Strain analysis is an inseparable part of Engineering and science-related subjects. To understand the measures of stress and strain, one needs to understand the basics of stress-strain. In this article, we have covered what stress-strain and their relationship along with the Hooke’s law for better understanding.