Stress - Definition, Unit, Types, FAQs

Stress - Definition, Unit, Types, FAQs

Edited By Team Careers360 | Updated on Nov 12, 2024 02:20 AM IST

What is Stress?

Stress definition is, the force that acts on a body of per unit area. The effect of stress causes strain in the material. Stress is the process which helps to deform the material. Stress in physics, helps us to understand the force that a material or object experiences.

What is the unit of stress?

Stress meaning, the force that acts on a material in a unit area.

So, The SI unit of stress is $\mathrm{N} / \mathrm{m}^2$ (pascal، Pa ).

The CGS unit of stress is dyne/ $\mathrm{cm}^2$.

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This Story also Contains
  1. What is Stress?
  2. What is the unit of stress?
  3. Types of Stress
Stress - Definition, Unit, Types, FAQs
Stress - Definition, Unit, Types, FAQs

Types of Stress

A. Tensile Stress or Normal Stress

The tensile stress definition is given below-

The external force per unit area of material resulting in a stretch of material is known as tensile stress. We say that the object is in tension. The subscript is a reminder that force acts perpendicular to the cross-section.

Tensile Stress

We define tensile stress at cross-section as ratio of force F to cross-sectional area A:

Normal stress=FA----(1)

This is a scalar quantity. The SI unit of stress is pascal. Equation (1) shows that 1 pascal equals 1 newton per square meter (N/m²) :

$1 \mathrm{~Pa}=1 \mathrm{~N} / \mathrm{m}^2$

The unit of stress is the same as that of pressure. Air pressure in automobile tires is typically around 300 kPa.

B. Shear stress or tangential stress

The figure shows a body being deformed by shear stress. A force acting in a generally horizontal direction especially or force that produces mountain folding and over thrusting.

Shear stress

C. Bulk stress or Volumetric stress

Thus, bulk stress or volume stress is also can be called as pressure.

Bulk stress or Volume stress=p=FA.

Bulk stress

Hooke’s Law

Hooke’s Law is defined as the ratio of stress to strain.

StressStrain=Hooke's Law (Elastic Modulus)

The relation between stress and modulus of elasticity:

  1. Young's Modulus Y=Tensile stress or Normal stressTensile strain or normal strain
  2. Shear Modulus G=Shear stress or tangential stress shear strain or tangential strain
  3. Bulk Modulus B=Normal stressVolume strain

Thermal stress

The stress which is developed due to the rise or fall in temperature is known as thermal stress.

Let us consider that a rod of length $L$ is fixed between two rigid walls and is heated to raise the temperature by $\Delta \theta$. Hence, due to the rise in temperature, there develops a strain which is represented by $\Delta L L$.

From Young's Modulus $Y=$ Stress/Strain
We get, Stress $=Y \times$ Strain $=Y \Delta L / L$.

Relation between Stress and Elastic Potential Energy

Elastic Potential energy is defined as total work that is done against the restoring force that stretches a material by any length.

The relation with stress is,

Elastic Potential Energy

$U=\frac{1}{2}$ Stress $\times$ Strain

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Frequently Asked Questions (FAQs)

1. Define stress in physics.

Stress meaning in physics, is the amount of force that acts on any material with unit surface area. It is the property by which we can understand the limit of deformation of any material.

2. What is the SI unit of stress?

The SI unit of stress is Nm2. The SI unit of stress is also considered to be Pascal.

3. What are the different types of stress?

There are mainly three types of stress in physics-

  1. Tensile stress or Normal stress: Tensile stress or normal stress is defined as the stress, when the force F acts normal to the surface of the material to a cross-sectional area A. The formula of tensile or normal or longitudinal stress is, Normal stress=FA. Normal stress is also known as longitudinal stress.

  2. Shear Stress or Tangential stress: Shear stress or tangential stress is defined as the stress where the forces F act tangentially to the opposite ends of an object of surface area A. The formula of shear or tangential stress is, Tangential Stress=FA.

  3. Bulk stress or Volumetric stress: Bulk stress or volume stress is defined as the force which acts tangentially on the surface of a body which causes a change in its volume or pressure. This stress symbol is, ∆p where p is pressure which can be written as p=F/A.

4. What is hoop stress formula?

The hoop stress formula is H=PDm/2t where, H= hoop stress, P = pressure, t = thickness of the pipe and Dm = diameter of the pipe.

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Without proper planning, this move may increase stress rather than reduce it.


I hope this answer helps you. If you have more queries then feel free to share your questions with us we will be happy to assist you.

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