钢框架梁柱连接节点在循环荷载作用下的破坏机理

The Northridge earthquake damage arouses the investigation of hysteretic behavior and collapse mechanism of beam-to-column connections in steel frame. Because of its complexity, most research works are carried out by experimental method. Few experimental results cannot fully reflect the influences of main design parameters. And some places on test specimens cannot be measured; collapse details are hard to be observed. In order to make a qualitative breakthrough on the present research state, it is quite necessary to perform a precise and systemic computer simulation on collapse mechanism for all kinds of beam-to-column connections under cyclic loading and give out aseismic design recommendations.A nonlinear finite element method (FEM) computer program--DDNSP has been worked out for this project, which takes the combination of isotropic elasto-plastic damage, mixed-hardening constitutive relationship into consideration. FEM Simulation is made on collapse mechanism of beam-to-column fully-welded connections under cyclic loading. Base on results of 33 modeling cases, parameters which influences hysteretic behavior are systematically analyzed. With material, geometry and contact nonlinear taken into account, a thorough computer modeling using ANSYS software is worked out on collapse mechanism of bolt-welded rigid connection, end-plate connection, double-angle connection, connection with cantilever beam bolted splicing, and modified connections, such as dog-bone, welded cover plate, welded haunch under cyclic loading. Base on results of 215 stimulation cases, all kinds of parameters which influences hysteretic behavior are quantitatively analyzed. Test results of 28 specimens verified FEM analysis, and also add to the current insufficient experiment database. The research work is systematic and thorough. Conclusions and suggestions are quite useful for revising relative design codes.

将材料损伤因子引入到混合强化大变形本构方程中,研究在循环荷载（地震及风震）作用下,钢框架梁柱焊接、高强螺栓连接节点的循环塑性、低周疲劳、局部屈曲相关破坏机理。针对工程中常用连接构造，提出节点计算模型，计算方法及计算程序编制，分析破坏机理。提出工程设计建议。增加此类节点的延性，防止在强烈地震作用下钢框架节点过早地发生脆性破坏。