Under load , the number of the micro - cracks increases ; the micro - cracks expand and eventually become macro - cracks , which result in the failure of the structure 在载荷作用下,微裂纹的数量增加,扩展最后变成宏观裂纹,从而导致结构的破坏。
It is very important to study the correlation of cyclical strain on the side of hole with fatigue life cycle for understanding the material damage and micro - crack initiation , and for preventing macro - crack initiation and propagation 研究孔边循环应变与疲劳循环次数的相关性,对于研究材料损伤及微裂纹的产生,预防宏观裂纹的产生及扩展具有十分重要的意义。
The material or structure used in practical engineering away have initial damage which gradually devepop from beginning of distortion to failure , in this process polymerization and development of micro - cracks will cause formation and expand of macro - cracks 在实际工程中使用的材料或构件及结构是存在初始损伤的,其从开始变形直至破坏,是一个逐渐劣化的过程,在这个过程中,微裂纹的聚合和长大造成了宏观裂纹的形成和发展。