Custom Search

## SIMPLE STRESSES AND STRAIN

_

Force per unit area or intensity of the forces distributed over a given section is called as intensity of stress on that section.

P = Axial load

A= Cross sectional area

A material is capable of offering the following kinds of stresses :-

1.

2.

The intensity of tensile stress is given by :

The corresponding strain is called a tensile strain

Tensile strain = (Increase in Length)/(Original Length)

Where dl is the change in length and l is the original length

Strain is a dimensionless term as it is a ratio of two lengths

**STRESS**: The force of resistance offered by a body against the deformation is called stress. The external force acting is called the load. The load is applied on the body while the stress is induced in the material of the body.It is shown is the above diagram.Force per unit area or intensity of the forces distributed over a given section is called as intensity of stress on that section.

P = Axial load

A= Cross sectional area

A material is capable of offering the following kinds of stresses :-

1.

__Normal Stress__– When the internal force is normal to the plane of section then the corresponding stress is called__normal stress__.2.

__Tensile Stress__– When the resistance is offered by a section of a member is against an increase in length, the section is said to offer a tensile stress.The intensity of tensile stress is given by :

The corresponding strain is called a tensile strain

Tensile strain = (Increase in Length)/(Original Length)

Where dl is the change in length and l is the original length

Strain is a dimensionless term as it is a ratio of two lengths

_ 3.
Compressive stress – If a bar is subjected to
pushing axial loads a resistance is developed against decrease in length. This
resistance is called a compressive resistance.

The intensity of compressive resistance is given by

The corresponding strain is called compressive strain

Compressive strain = (Decrease in length)/(Original length)

4. Shearing Stress - When the internal force are existing in the plane of the section and their resultant is equal to F are called shearing forces and the corresponding stress is called shear stress.It is represented by the formula

5. Bearing Stress - Bolts, Pins and rivets create stress in the member they connect, along the bearing surface or surface of contact.These forces are developed on the inside surface or the body and the corresponding stress is called Bearing stress.

The intensity of compressive resistance is given by

The corresponding strain is called compressive strain

Compressive strain = (Decrease in length)/(Original length)

4. Shearing Stress - When the internal force are existing in the plane of the section and their resultant is equal to F are called shearing forces and the corresponding stress is called shear stress.It is represented by the formula

5. Bearing Stress - Bolts, Pins and rivets create stress in the member they connect, along the bearing surface or surface of contact.These forces are developed on the inside surface or the body and the corresponding stress is called Bearing stress.

## STRESSES ON AN OBLIQUE PLANE UNDER AXIAL LOADING

A section forming an angle theta with a normal p

The Normal Stress is calculate as follows

The Shearing Stress has the value as follows

The below diagram shows the stresses developed on the oblique plane

## COMPLEMENTARY STRESSES

Now a plane is considered which is inclined at an angle of 90 degree with the above mentioned case.

It will look something as follows

The relation between the stresses on the oblique plane and the complementary stresses is as follows :

It will look something as follows

The relation between the stresses on the oblique plane and the complementary stresses is as follows :