Young's Modulus

Is a measure of the stiffness of a given material. It is defined as the ratio, for small strains, of the rate of change of stress with strain. The Young's modulus allows the behavior of a material under load to be calculated. For instance, it can be used to predict the amount a wire will extend under tension, or to predict the load at which a thin column will buckle under compression. Some calculations also require the use of other material properties, such as the shear modulus, density, or Poisson's ratio.

The SI unit of modulus of elasticity (Y) is the pascal. Given the large values typical of many common materials, figures are usually quoted in megapascals or gigapascals. Some use an alternative unit form, kN/mm2, which gives the same numeric value as gigapascals. The modulus of elasticity can also be measured in other units of pressure, for example pounds per square inch.

See Also

Shear Modulus and Bulk Modulus.