Wednesday 18 December 2019

Chapter-5- Pure Axial Loading

Pure Axial Loading

A member is said to be under pure axial loading, when two equal and opposite load act along the axis of the member in such a way that its magnitude remains constant throughout the length of the member. In this, we have assume that member is a prismatic bar (i.e. dimension are same throughout the structure).


pure axial load
Pure Axial Load 

Under axial loading condition we found that bending momentshear force and twisting moment are zero.

SFD & BMD Diagram
SFD & BMD Diagram

There are many method in strength of material to obtains the stress occurred on member due to application of pure axial loading, here we have considered stress calculation as per “section method” which say that load acting to any cross section is equal to algebraic sum of corresponding load either on the left hand side of the cross section or on the right hand side of the cross section of the member.

 We see in the below image that at the section x-x axial load is “P” and Shear force, bending moment and twisting moment is “0”.

 Axial load is also independent of location of section x-x which signify that axial load is constant, so we can say that member is under pure axial load. We can calculate stress and deformation caused due to axial load using below equation.


Stress and Deformation
Stress and Deformation

Above equation is only applicable when it satisfied following condition.

  • Member should be prismatic whose magnitude remains constant throughout its length.