【作者】 陈立保；

【导师】 陈明祥；

【作者基本信息】 武汉大学 ， 工程力学， 2004， 硕士

【摘要】 本文以ABAQUS为平台，建立一套分析钢管混凝土的有限元模型。其中核心混凝土采用混凝土损伤塑性模型，钢管采用弹塑性模型，界面采用节理模型。在轴压、纯弯和压弯情况下分析钢管混凝土柱力学性能受混凝土强度、含钢率和钢材屈服强度等参数的影响规律及其破坏机理。具体的工作有以下几个方面： 1．模型验证 选取有代表性的Kupfer混凝土双轴材料试验，使用混凝土损伤塑性模型进行计算模拟，计算结果与试验结果具有较好的一致性，说明混凝土损伤塑性模型能够很好地模拟混凝土力学性能。 选取有代表性的轴压、压弯钢管混凝土结构试验，使用建立的有限元模型进行计算分析，并与试验结果相比较。结果表明，两者具有较好的一致性，从而验证了建立的模型能较好地模拟钢管混凝土极限承载力和破坏全过程。 2．力学性能分析 用建立的有限元模型进行计算分析在轴压、纯弯和压弯三种情况下混凝土强度、含钢率和钢材屈服强度对方钢管混凝土极限承载力的影响。在含钢率相同情况下，与圆钢管混凝土比较承载力以及荷载位移曲线的差别。 轴压情况下，采用节理模型考虑界面影响，界面之间随机挖去一定比例单元，模拟空隙率影响。压弯情况下，计算分析方钢管混凝土构件受偏心距、轴压比以及长细比等参数的影响，并分析随轴压比增大延性降低，结构变脆的机理。 3．提高承载力措施 在上面分析的基础上，提出一种提高方钢管混凝土极限承载力和延性的方法，即采用对穿钢筋锚固。计算分析结果表明，该方法效果明显。更多还原

【Abstract】 This paper presents a finite element method (FEM) model for the analysis of concrete filled steel tubes (CFT) based on ABAQUS. The damage plasticity model is used to describe core concrete and elastic-plasticity model to describe the steel tube. The jointed material model is used to model interface between the concrete and the steel tube. Under the condition of axial compression, simple bending and compression-bending, the effects of parameters to CFT’s mechanical performance are studied. The parameters taken in account are concrete compression strength, steel ratio, steel strength.Details are listed below:1. Model verificationThe representative experiment (Kupfer, concrete biaxial material experiment) is selected for verification of the concrete damage plasticity model. Results have shown that the model is appropriate.Representative structural experiments of CFT subjected to axial compression and compression-bending are selected to verify the FEA model presented in this paper. The results of the FEM analysis agree well with the experiments. This shows that the FEA model does well with the simulation of CFT’s ultimate bearing resistance and full failure process.2. Mechanical performance analysisUnder the condition of axial compression, simple bending and compression- bending, the effect of main parameters to CFT and failure mechanism are studied. The parameters taken in account are concrete compression strength, steel ratio, steel strength. With the same steel ratio, square CFT is compared with circle CFT in bearing resistence and load-deformation curves.Under axial compression, influence of interface is considered using jointed material model, and gap of interface is considered by removal of some elements. Moreover, the influence of different parameters, such as eccentricity, axial load ratio and slenderness ratio are studied under compression-bending. Also, analysis of the mechanism that ductility reduces and structure becomes brittle with increasing axial load ratio is performed.3. Method for enhancement of bearing resistenceOn the basis of the above analysis, a method is developed to improve the ultimate bearing resistance and ductility of CFT. That is to add transverse reinforcement steel bar to CFT. Computational results show that the method is efficient.更多还原