Young's modulus
Introduction
The Young's modulus (longitudinal elastic modulus) is a parameter that characterizes the behavior of an elastic material "Elasticity (solid mechanics)") (the parameter may depend on the direction in which a force is applied for anisotropic materials). For linear elastic materials it can be defined as the ratio between tension in the direction of application of a force and the corresponding deformation, for non-linear elastic materials the derivative of the stress with respect to the deformation is usually used.
Etymology
The term module comes from the Latin modulus, diminutive of modus: “measurement”.
History
This behavior was observed and studied by the 19th century English scientist Thomas Young, although the concept was developed in 1727 by Leonhard Euler, and the first experiments using the concept of Young's module in its current form were done by the Italian scientist Giordano Riccati in 1782 (25 years before Young's work).[1].
Description
For a linear elastic material #Linear_Elasticity_Theory "Elasticity (solid mechanics)") and isotropic material, the Young's modulus has the same value for traction as for compression, being a constant independent of the effort as long as it does not exceed a maximum value called the elastic limit, and is always greater than zero: if a bar is pulled, it increases in length.
Both the Young's modulus and the elastic limit are different for the various materials. The modulus of elasticity is an elastic constant that, like the elastic limit, can be found empirically by tensile testing of the material. In addition to this longitudinal modulus of elasticity, the transverse modulus of elasticity of a material can be defined.