【作者】 王萌；

【导师】 石永久；

【作者基本信息】 清华大学 ， 土木工程， 2013， 博士

【摘要】 在强烈地震作用下，传统的杆系模型对于钢框架的构件、节点发生承载力和刚度退化特征无法准确模拟和预测，往往会低估结构变形、高估结构抗倒塌能力，存在一定的安全隐患。本文对钢框架的损伤退化机理、关键影响参数及损伤退化过程进行了深入研究，提出了能够更准确模拟整体结构损伤退化行为的理论模型。通过程序开发，实现了钢框架杆系模型考虑损伤退化全过程的弹塑性动力时程分析，发展了一种有效的强震分析手段。论文的工作主要包含以下六个方面：（1）对比研究十种损伤指数模型对参考文献中两批节点试验损伤退化过程的描述，探讨不同损伤指数模型对结构破坏预测的准确性，并分析不同模型的适用范围（第2章）。（2）完成50个Q235B和Q345B钢材在10种加载制度下的循环加载试验，提出了考虑循环强化作用的钢材滞回本构模型SHCM（Steel Hysteretic ConstitutiveModel）。利用有限元软件ABAQUS，二次开发了相应计算程序，并得到大量试验验证，为后续提出考虑损伤退化的等效本构模型提供了基础理论框架（第3章）。（3）结合已有构件和节点试验，在第3章模型研究的基础上，提出了能够准确模拟累积损伤退化现象、预测损伤退化全过程的数值分析方法（第4章）。（4）基于第4章研究成果，对构件、节点进行参数分析，深入剖析损伤退化控制因子及其影响程度、损伤退化过程及“三折线”退化曲线分布规律（第5章）。（5）建立了考虑损伤退化行为的“等效本构模型”，利用定义损伤退化控制因子对结构地震响应进行深度描述。利用ABAQUS软件平台二次开发了能够进行损伤退化全过程分析的用户材料子程序DDAP （Damage and DegradationApplication Program）。模型得到了已有钢框架静力试验和振动台试验的充分验证,并应用于北岭地震实际破坏的钢框架变形以及损伤预测中（第6章）。（6）通过与壳单元模型、多尺度模型及传统杆系模型进行比较，证明本文提出的考虑损伤退化的等效本构模型提高了钢框架杆系模型在强烈地震作用下动力时程分析和破坏预测的准确性，兼顾计算效率，为强震分析提供技术支持。在此基础上，得到了累积损伤退化对不同层数钢框架抗震评价指标的影响程度和规律，并提出了用于损伤破坏控制的退化指数预测曲线（第7章）。本论文在国家自然科学基金项目（编号：90815004和51038006）资助下完成。更多还原

【Abstract】 For members and connections in steel frames, the damage and degradationcharacteristics of strength and stiffness could not be efficiently simulated and predictedby traditional beam element model subjected to strong earthquakes. The deformation ofstructural system would be underestimated and the collapse performance would beoverrated, leading to potentially unsafe structures. In this thesis, the critical parameters,including damage and degradation mechanism, that influence damage evolution processof steel frames were firstly studied in depth. Then，a theoretical model was proposed tosimulate the damage and degradation behaviors of full frame structures more accurately.By developing the algorithm based on ABAQUS platform, elastic-plastic time historyanalysis with beam element model was implemented for the complete process ofdamage and degradation. An effective analysis approach of steel frames under strongearthquake was developed.The main work of this thesis consisted of six parts:(1) Damage and degradation properties of two series tests with ten damage indexmodels were compared. The accuracy of different damage index models for predictingstructural damage were investigated. The application scopes of different models werealso discussed.(Chapter2).(2)50specimens of Q235B and Q345B grade steel under10cyclic loadingpatterns were tested. A steel constitutive theoretical model, Steel Hysteretic ConstitutiveModel (SHCM), considering cyclic hardening characteristics was proposed. Based onthe finite element program ABAQUS, a corresponding calculative program wasdeveloped. Then the model was verified by available material and component tests,which provided the basic theoretical framework for equivalent constitutive modelconsidering damage and degradation behaviors.(Chapter3).(3) According to the referred component and connection tests results, using thesteel skeleton curve model considering cyclic hardening in Chapter3, the numericalanalysis method was proposed for accurately simulating the cumulative damage anddegradation phenomenon and efficiently predicting the complete process of damage.(Chapter4). (4) Based on the research results of Chapter4, a large number of parametricanalysis were carried out for components and connections. The influencing factors andimpact degrees of damage and degradation, the damage evolution process, as well as thedistribution law of the "tri-linear" degradation curve were analyzed in depth.(Chapter5).(5) An equivalent steel constitutive model considering damage and degradationbehaviors was established, and damage factors was defined to describe the seismicbehaviors of steel frame in details. Based on the ABAQUS software platform, auser-defined material program, Damage and Degradation Application Program (DDAP),was developed for analyzing the whole process of damage and degradation. The DDAPwas verified by available steel frame tests, including static cyclic tests and shaking tabletests. The model was also used for predicting the deformation and damage of a real steelframe damaged under Northridge earthquake.(Chapter6).(6) By comparing with shell element model, multi-scale model and the traditionalbeam element model, the proposed model considering damage and degradation wasproved to improve the precision of time history analysis and failure prediction of steelframe under strong earthquake significantly. The model was also a balanced solution inboth computational accuracy and efficiency, which provided technical assistance fordynamic analysis under severe earthquake. Based on this analysis method, the effectsand properties of cumulative damage and degradation on seismic evaluation indicatorsof multi-storey steel frames were obtained, and the predicting curve of the degradationindex was proposed for damage and failure control.(Chapter7).This dissertation was sponsored by the National Natural Science Foundation ofChina (NSFC) program (No.90815004and No.51038006).更多还原