高强钢氢致滞后断裂滞后时间的有限元预测

基于氢相关的内聚力模型，开发了顺次耦合的氢致滞后断裂有限元计算程序，预测了预含氢AISI4135高强钢圆棒缺口试样在常载荷拉伸条件下的滞后断裂时间，并考察了试样初始平均含氢水平对滞后断裂的影响.结果表明，氢相关的内聚力模型可有效预测氢致滞后断裂的断裂时间，有限元预测结果和相关报道较为一致.氢致滞后断裂存在氢临界值，当缺口尖端应力集中区聚集的氢浓度达到临界时裂纹开始形核，此临界值和结构的初始含氢量无关.

Prediction of Hydrogen Induced Delayed Fracture Initiation Time of High Strength Steel Using Cohesive Zone Modeling

A sequential coupling calculation method on hydrogen induced delayed fracture was developed based on cohesive zone modeling (CZM) by using finite element program-ABAQUS. Using this method, the fracture initiation time was numerically predicted for circumferentially notched round bar specimen of AISI4135 high strength steel under a constant load after electrochemically pre charged. The effect of various hydrogen contents was also considered. The results show that the hydrogen dependent CZM can be used in the prediction of failure in actual structures. The predictions of the time to fracture are in good quantitative agreement with the some experimental results. The delayed fracture occurrs when a critical hydrogen concentration at the location of max hydrostatic stress is reached by diffusion. The critical hydrogen concentration is not dependent on initial hydrogen content.