Explanation

The materials can recover its original state after removing the external force. The deformation that can disappear after the external force is removed is called elastic deformation. The parameters reflecting elasticity properties of materials include proportional limit, elasticity limit and Poisson's ratio. The maximum stress in a proportional relationship between stress and strain is called the proportional limit. The maximum stress that can recover after unloading is called the elasticity limit. In the elasticity range, the ratio of normal stress to normal strain is called elasticity (Young's) modulus E; The ratio of shear stress to shear strain is called shear modulus. The ratio of lateral shrinkage to longitudinal elongation is called Poisson's ratio. elasticity can be divided into three categories: linear elasticity, non-linear elasticity, and anelasticity. The linear elasticity refers to the relationship between stress and strain as a linear median. The non-linear elasticity refers to the relationship between stress and strain that does not meet the linear relationship, but still maintains a single value relationship. It is called anelasticity when the stress and strain meet the linear relationship after a certain period of time after loading.

Classification