Young's Modulus(Elastic Modulus):

Young's Modulus (many times referred to as Modulus of Elasticity, meaning "measure" of elasticity) is an extremely significant features of a material. It is the numerical evaluation of the Hooke's Law, specifically the ratio of stress to strain (the  measure  of  resistance to elastic deformation). For calculate Young's Modulus and stress (at any point) below the proportional limit is separated through corresponding strain. It could also be calculated as the slope of the straight-line portion of the stress-strain curve.   (A positioning on a stress-strain curve will be elaborates later.)

E = Elastic Modulus = stress/strain = psi/in./in. = psi

or

E =σ /ε                                                                       (1)

We could now see in which Young's Modulus might be simply calculated, given that the stress and corresponding unit elongation or strain have been determined through a tensile test as described earlier. The Strain (ε) is a number representing a ratio of two lengths; thus, we could conclude in which the Young's Modulus is measured in the similar units as stress (σ), which is, in pounds per square inch.  Table 1 provides average values of the Modulus E for various metals used in DOE facilities construction.  The Yield strength and ultimate strength will be elaborates in more detail within the next lesson.