基于不同强化准则的扩大孔梁柱节点延性断裂预测

Prediction of ductile fracture for enlarged-scallop beam-column connection based on different hardening rule

钢结构节点的延性损伤破坏行为预测可为工程设计和工程加固提供参考,而材料强化模型的选择会影响到预测结果.以具有一定延性的扩大孔梁柱节点为研究对象,采用ABAQUS有限元隐式分析方法,引入微观机制进行延性断裂预测.考虑长周期地震动作用影响施加2种幅值的大位移常幅循环荷载,基于常用的2种强化准则建模分析,并与对应的既有试验结果相比较,结果表明:基于等向强化准则的模拟结果中刚度退化程度较试验严重,开裂路径的预测也与试验结果有偏差;基于随动强化准则的模拟结果则呈现出相对吻合的态势,开裂起始时间受强化准则的影响不明显.

The prediction on ductile damage and fracture behavior of steel connections can provide some reference for engineering design and engineering reinforcement;however, the choice of material hardening model may affect the prediction results. In this paper, the enlarged-scallop beam-column connections with certain ductility are taken as the research object,the ABAQUS finite element implicit analysis method is adopted, and micromechanics is introduced for ductile fracture prediction. Considering the impact of long-period ground motions, the two kinds of equal amplitude cyclic load with the large displacement are applied. After the modeling based on two kinds of commonly used hardening rules, the analyses are performed, and the results are compared with the corresponding existing test results. It is indicated that the degree of stiffness degenerated in the simulation results based on the isotropic hardening rule is more severe than that of the experiment, and the prediction of the cracking path deviates from the experiment trend. The simulation based on the kinematic hardening rule shows a relatively consistent result, and the crack initiation time is not obviously affected by changes in the hardening rule.