## Scope

TO DETERMINE YOUNG’S MODULUS OF STEEL: This test determines young’s modulus of mild steel when subjected to an axial tensile load. (ASTM E111-04).

## Significance

Tensile Modulus also called Young’s Modulus alt. Modulus of Elasticity – is a measure of the stiffness of an elastic material. It is used to describe the elastic properties of objects like wires, rods or columns when they are stretched or compressed.

Tensile Modulus is defined as the

“ratio of stress (force per unit area) along an axis to strain (ratio of deformation over initial length) along that axis”

It can be used to predict the elongation or compression of an object as long as the stress is less than the yield strength of the material. More about the definitions below the table.

The value of young’s modulus is a material property useful in design for calculating compliance of structural materials that follow Hooke’s law when subjected to uniaxial loading (that is, the strain is proportional to the applied force).

## Apparatus

Universal Test Machine (UTM), Specimen, Measurement apparatus: Vernier Calipers, Steel ruler and strain gauges

## Procedure

• Measure the diameter of the specimen at 3 various places and calculate the average.
• Mark the gauge length on the specimen.
• Fix the specimen to the machine by pushing the top grip upwards and inserting the specimen into the bottom grip.
• Remove the specimen from the grips and join back the broken halves together and measure the final “gauge” length and the diameter at the broken section.

## Observations & Calculations

Specimen diameter                 =                      mm
Cross sectional area               =                      mm2
Specimen Gauge Length (L)    =                      mm
Strain rate                               =                      mm/min

## Results

• Plot the stress-strain graph
• From the stress-strain graph
• Determine Elastic Modulus (E)

Elastic Modulus, (E) =

OR

Elastic Modulus, (E) = Slope of Graph
Stress =
Strain (ε) =
Elastic Modulus (E)=

## Precautions

• Plot the graph carefully.