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交变载荷断裂力学主要研究材料或结构在交变载荷作用下的疲劳断裂机理、材料或结构中的不扩张的非活性裂纹容限,以及活性裂纹由初始值 a_o 到失稳扩展临界值 a_c 的扩展规律,即所谓裂纹亚临界扩展规律。从而对具有裂纹的工程结构进行无限寿命设计,确定疲劳载荷作用下不发生亚临界扩展的非活性裂纹容限及估算具有活性裂纹的工程结构的有限剩余寿命,达到安全使用的目的。国内外多数研究工作者运用线弹性断裂力学中的应力强度因子理论、弹塑性断裂力学中的 COD 理论、J 积分理论来研究活性裂纹在线
Fracture Mechanics of Alternating Load The mechanism of fatigue fracture of material or structure under alternating load, the non-expanding non-active crack tolerance in material or structure, and the change of active crack from initial value a_o to instability extended critical value a_c The law of expansion, the so-called crack subcritical expansion law. Therefore, the design of infinite life of cracked engineering structures, the determination of the non-active crack tolerance without subcritical expansion under fatigue load, and the limited residual life of engineering structures with active cracks are determined to achieve the safe use. Most domestic and foreign researchers use the theory of stress intensity factor in linear elastic fracture mechanics, COD theory in elastic-plastic fracture mechanics and J integral theory to study the influence of active crack on-line