高温下节点加腋前后应力响应非线性分析

NONLINEAR FINITE ELEMENT ANALYSIS OF STRESS REPONSE OF HAUNCHED JOINTS AND NORMAL JOINTS AT HIGH TEMPERATURES

采用有限元软件ANSYS/Workbench,建立钢结构加腋节点三维有限元模型,通过对比加腋节点和非加腋节点分别在外荷载、温度荷载、热力耦合3种情况下的应力分布规律以及各个方向应变分布,判断节点加腋前后受力的影响和变化。结果显示,在无温度场影响的情况下,加腋可以有效降低梁柱节点最大荷载,使下部节点处塑性铰外移。而在受火情况下,钢梁柱温度曲线呈梯度非线性变化,加腋钢框架升温速度要略慢于非加腋钢框架。施加外荷载时,腋的作用被削弱,上翼缘梁柱节点会比腋与下翼缘连接处更早产生塑性铰。

A 3D finite element model of steel structure of haunched joint was constructed by using the finite element software ANSYS Workbench,and the haunching ＇s effects and changes were estimated by comparing the differences between hauched joints and normal joints in distribution rules and distribution changes in each direction under these three circumstances： external load,temperature load and coupled thermal-mechanical. The results showed that in the noneffect temperature field,hauching could decrease the beam-column joints＇ maximum stress and then the plastic hinge,which wass in the bottom,was out-shift. However,when the circumstance turned to the high-temperature environment,the steel beam-column＇s temperature curve was non-linear,and the warming of steel frame with haunching was slightly slower than that of non-haunching. Furthermore,if the steel frame was added extra external stress,the power of haunching would weaken. Thus,the plastic hinge would appeared on top flange beam-column joints faster than that on bottom flange joints.