开裂的概念和理论开裂的极端类型是脆性开裂和韧性开裂。Griffith理论认为:断裂功转化为断裂表面的表面能,脆性材料的强度由裂缝决定。断裂力学认为材料都是有缺陷的,因而引发裂缝,导致开裂。微观研究发现了有些脆性高聚物在应力作用下产生银纹,银纹当中有一些高度取向的大分子链束,这些大分子链断裂以后就发展成裂缝。韧性开裂往往跟屈服和冷拉伸相联系。当局部应力达到屈服应力时,这一局部迅速形变,而应力反而下降或几乎不变。以后就在 Concept and Theory of Cracking The ultimate types of cracking are brittle and ductile. According to Griffith’s theory, the fracture energy transforms into the surface energy of the fracture surface, and the strength of the brittle material is determined by the fracture. Fracture mechanics that the material is flawed, thus triggering cracks, leading to cracking. Micro-studies have found that some brittle polymers produce silver grains under stress, and some highly oriented macromolecular chains among the silver grains develop cracks after they are broken. Toughness cracking is often associated with yielding and cold drawing. When the local stress to yield stress, this part of the rapid deformation, but instead of stress or almost unchanged. In the future