Modulus of Elasticity

This may be noticed that in most materials that might be ductile or brittle, the elastic behaviour is marked via linear relationship between strain (ε) and stress (σ). It is seen for A and B type ductile materials in Figure of Stress-strain Diagram for Ductile Materials and for type A brittle material in Figure of Stress-strain Diagram for Brittle Materials. That linear connection was first identified throughout law of Hooke that states like: "stress is directly proportional to strain (ε) surrounded by elastic limit." It as:

                                                                     σ ∝ ε

                                                  σ = E ε that is E = σ/ε.................................Eq(1)

The constant of proportionality E is termed as Modulus of Elasticity or Young's Modulus. Apparently the elastic slope part of stress-strain (ε-σ) diagram as shown as oa in Figures of Stress-strain for Ductile Material and Stress-strain for Brittle Materials is the modulus of elasticity. Modulus of elasticity is a constant for a specified class of material and variation in minute alloying contents does not reason change in E. For instance, wide range of carbon steel had E = 210 × 103 MPa. If stress-strain curve is recognized accurately the elastic part slope is E of the material. Conversely, it might be noted such this is not a reliable method since tension tests require such loads as may reason minute deformations in loading system, part of that may see like deformation of the specimen.