Let’s start with a question.
“What is modulus of elasticity?” . The first and general answer by students would be
“It is stress divided by strain”
Does this answer make sense to a 5th grader?
We often fail to comprehend scientific terms in a qualitative manner. What might actually be the significance of modulus of elasticity? You might know and ‘feel’ stress and strain. But many people don’t know and ‘feel’ modulus of elasticity. What exactly means when we say modulus of elasticity of steel is 200 GPA?
Modulus of elasticity is also called Young’s modulus or Elastic modulus.
We all know the famous stress strain graph where we can find yield stress and ultimate tensile stress of a material.
In the graph, there is this linear stress region where Hooke’s law makes sense. It is also the region where the material when deformed tends to revert back to original. Think of a rubber, when it is stretched(and then released) it returns back to its original state.
Again think of a glass, Is it ‘rubbery’? Glass does not show the ‘rubbery’ property on application of nominal stress. It is what we call ‘stiff’. Stiffness is often confused with strength. So you can think of above mentioned examples to differentiate between stiffness and strength.
That is where modulus of elasticity comes into account. Modulus of elasticity qualitatively defines whether the material is ‘rubber’y or ‘glassy’.
The more the value of modulus of elasticity of a material, the more stiff the material is. The more the modulus of elasticity is, the more easier it is to induce temporary deflection in a material.