【作者】 刘鹏；

【导师】 刘璐；

【作者基本信息】 哈尔滨工业大学 ， 土木水利（专业学位）， 2025， 硕士

【摘要】 传统自复位支撑钢框架在强震下易出现节点应力集中和残余变形问题,影响结构的抗震性能和震后可恢复功能。现有研究对削弱梁截面(RBS)在自复位体系中的应用尚不充分,且节点域剪切变形的影响常被简化,导致分析结果可能偏于不安全。鉴于此,本文开展了以下系统性的理论分析和数值模拟研究:完成考虑削弱梁截面的无芯自复位支撑钢框架的设计。通过控制翼缘削弱起点、削弱长度、削弱深度等关键参数,设计出3组共9个削弱梁截面。用ABAQUS软件构建精细化有限元模型,开展考虑削弱梁截面的无芯自复位支撑钢框架拟静力分析。通过与未加削弱梁截面的结构对比发现,引入削弱梁截面后,框架滞回曲线更为饱满,节点域应力集中现象显著改善,验证削弱梁截面在引导塑性铰外移以及增加框架侧向弹性变形能力方面的有效性。分析削弱长度、深度及起始位置对整体框架极限承载力、延性系数、部件耗能占比及等效粘滞阻尼比的影响,并给出设计建议,以提高节点延性和耗能能力,实现“强节点、弱构件”的抗震设计目标。为提升非线性时程分析计算效率,进行多尺度有限元建模。将节点域和削弱梁截面简化为旋转弹簧单元,支撑系统等效为非线性弹簧单元,并通过Pushover分析和模态分析验证该简化方法。对四种多尺度模型进行小震、中震及大震下的弹塑性时程分析,探讨削弱梁截面及节点域剪切效应对四种不同结构的顶点位移、层间位移角、基底剪力及塑性铰分布的影响。发现节点域剪切变形对框架侧向刚度的影响较大,当忽略节点域剪切变形时,框架顶点位移、层间位移角及基底剪力的预测值均偏于危险。削弱梁截面通过牺牲局部刚度及强度换取整体结构的延性和耗能能力,以有限地增加框架的顶点位移为代价,显著地减小框架基底剪力。更多还原

【Abstract】 Traditional self-centering braced steel frames are prone to stress concentration at joints and residual deformation under strong earthquakes,which adversely affects their seismic performance and post-earthquake recoverability.Current research remains insufficient regarding the application of Reduced Beam Sections(RBS)in self-centering systems,while the influence of shear deformation in panel zones is frequently oversimplified,potentially leading to unconservative analytical results.To address these issues,this paper conducts systematic theoretical analyses and numerical simulation studies focusing on:Three groups comprising nine reduced beam sections were designed by controlling key parameters including flange weakening start point,length,and depth.A refined finite element model was established using ABAQUS to conduct quasi-static analysis on the self-centering braced steel frame with reduced beam sections.Comparative studies with non-weakened structures demonstrate that the weakened sections yield fuller hysteretic curves,significantly alleviate stress concentration in panel zones,and validate their effectiveness in relocating plastic hinges outward while enhancing lateral elastic deformation capacity.Parametric analyses quantify the impacts of weakening length,depth,and position on ultimate bearing capacity,ductility coefficient,energy dissipation distribution,and equivalent viscous damping ratio.Design recommendations are proposed to enhance joint ductility and energy dissipation,achieving the"strong joint-weak component"seismic design objective.To improve computational efficiency for nonlinear time-history analysis,a multi-scale finite element modeling approach is implemented.Panel zones and reduced beam sections are simplified as rotational spring elements,while the bracing system is equivalently modeled as nonlinear springs.The simplification is verified through pushover analysis and modal analysis.Elastoplastic time-history analyses under minor,moderate,and major earthquakes are conducted for four multi-scale models.The effects of reduced beam sections and panel zone shear deformation are investigated through comparisons of roof displacement,inter-story drift ratio,base shear,and plastic hinge distribution.Results indicate that neglecting panel zone shear deformation leads to unsafe underestimation of roof displacement,drift ratio,and base shear.The reduced beam sections strategically sacrifice local stiffness and strength to enhance global ductility and energy dissipation capacity,effectively reducing base shear at the expense of marginally increased roof displacement.更多还原