Explanation

When loading in the elasticity range, only after a certain period of time can the elasticity strain (or elasticity stress) reach the equilibrium value corresponding to Hooke's Law (that is, there is a non single linear relationship between stress and strain). It has two forms, one is called strain relaxation or elasticity aftereffect, and the other is called stress-relaxation. Adding elasticity stress produces an instantaneous strain, and in the process of keeping constant, the elasticity strain increases with time until the equilibrium value. The phenomenon that elasticity strain increases with time under constant stress is called anelasticity creep (or micro creep). If unloading, part of elasticity strain will disappear instantaneously, and the remaining elasticity strain will gradually recover to zero, which is called elasticity aftereffect. anelasticity creep and elasticity aftereffect are called strain relaxation, which is a form of anelasticity.

Classification