What The Heck Is Modulus of Elasticity?

The Machinery's Handbook defines Modulus of Elasticity as follows: "Modulus of Elasticity, E, (also called Young's modulus) is the ratio of unit stress to unit strain within the proportional limit of a material in tension or compression". In general, the Modulus of Elasticity, for steel is 30,000,000 p.s.i. Some steels are as low as 28,000,000 and some as high as 34,000,000 p.s.i.

Stress equals the force or load applied divided by the area that the force is applied to, or Stress=F/A.

Strain is the deformation, elongation or compression, that the material undergoes as a result of the force being applied to it.

The shear Modulus of Elasticity, G, also known as the Modulus of Rigidity, is also the ratio of stress to strain within the proportional limit of a material, but in shear. It is usually expressed as a percentage of the Modulus of Elasticity, E, in tension. The Modulus of Elasticity in shear, G, is usually about 38% of the Modulus of Elasticity in tension, E.

Some values for Modulus of Elasticity for some common materials are as follows:

Aluminum, Alcoa QC-7 10,300,000 p.s.i., or 71,000 MPa

Brush-Wellman's Moldmax XL Beryllium Copper 17,000,000 p.s.i. or 117,000 MPa

Brush-Wellman's Protherm Beryllium Copper 20,000,000 p.s.i. or 138,000 MPa

Ampco MoldMATE 90 22,000,000 p.s.i. or 152,000 MPa

Steel 30,000,000 p.s.i. or 207,000 MPa