Elongation stands for a mechanical property of metal i.e. the degree to which a material is supposed to be delivered, stretched, or compressed prior to rupture. It is a point among tensile strength and yield strength and is presented as a percentage of the original length.

##### Purpose of Elongation

Elongation is a measure of ductility, which provides confidence that metals can be formed, without cracking or fracturing In rebar, it defines ductility so that bars can be bent without cracking. – If bars do not crack during fabrication, any excess elongation is irrelevant.

This construction video tutorial focuses on the following topics

1-  Finding out the elongation of the bar as soon as the load is applied
2- The elongation of a steel rod under a specific load
3- The source from which the formula for elongation is derived

In this video, the solution is given to the following problem :

Problem: Find out the length of a mild steel rod after providing 100 kips force/load. Suppose the diameter and length of rod are ½” and 36 inches.

The following formula is used to provide the solution :-

Elongation = FL/AE
Here F stands for applied force/load
L stands for the length of the specified rod
A stands for cross-sectional area of the rod

E stands for the modulus of elasticity of the material
Here, all the values are given except cross-sectional area:-
The cross-sectional area is determined with the following formula:-
A = πD2 /4