【作者】 陈辉；

【导师】 陈军明；

【作者基本信息】 武汉理工大学 ， 工程力学， 2010， 硕士

【摘要】 钢管对核心混凝土的紧箍作用是钢管混凝土结构技术的关键力学问题之一,这一界面力学问题的准确描述是解决问题的关键,矩形截面的钢管混凝土结构尤其如此。本文基于连续介质力学方法,建立钢管混凝土小变形下的弹性分析理论,重点对矩形钢管混凝土柱的弹性本构关系、组合弹性模量、组合轴压刚度以及界面力学问题进行深入的理论研究、数值模拟。主要工作和结论如下：1、基于连续介质力学理论,结合弹性力学平面问题相关理论和结构力学位移求解方法,建立了钢管混凝土柱小变形条件下的界面力学问题的弹性分析理论,并借助matlab工具实现矩形钢管混凝土柱的弹性本构关系、组合弹性模量、组合轴压刚度以及界面力学问题数值求解。2、获得了钢管混凝土组合柱的界面法向力(紧箍力)的分布函数表达式f1(x)和f2(y)。运用函数的图像能方便地描述界面紧箍力的分布规律。图像表明：方形截面和矩形截面的钢管混凝土界面法向力的分布很不均匀(呈类似二次曲线的形状),矩形截面比方形截面的紧箍力的分布更加的不均匀。在角点处都有应力集中的现象,角点的紧箍力最大,在中点处的紧箍力最小,方形截面的钢管混凝土紧箍作用比矩形截面的钢管混凝土要大。3、研究了组合弹性模量的变化规律。随着含钢率的增大而明显增大；随着混凝土的强度等级的增高仅略有增大。研究也表明在相同的含钢率ρ下,截面的边长比在a／b≤2.4范围内,矩形钢管混凝土组合弹性模量比方形钢管混凝土组合弹性模量略小,差值在5%左右,故此范围矩形截面可以近似的等效为正方形的截面处理。此结论与文献[12]一致。4、研究表明：钢管混凝土的组合弹性模量、组合轴压刚度要比目前采用的没有考虑紧箍作用的换算弹性模量、换算轴压刚度要高,在计算范围内,组合弹性模量比换算弹性模量提高约1.36%-15.3%,组合轴压刚度要比换算刚度提高约1.58%-20.1%。且随含钢率的增大而显著增大,随混凝土强度的提高而变化不大。更多还原

【Abstract】 One of the key of mechanical problems of concrete-filled steel tube(CFT) structure is the confining effect between the steel tube and the core concrete. The key to solve the problem is to accurately describe the interfacial mechanics problems,especially to the rectangular section of CFT. The paper based on continuum mechanics theory, made a small-deformation elasticity theory analysis on rectangular concrete-filled steel tube column(CFTC). Focus on the elastic constitutive relation, compounding elastic modulus、compounding axis direction compressive stiffness and interfacial mechanics problems to rectangular CFTC of theoretical study deeply and numerical simulation.The main conclusions of the paper as follows:(1) Based on continuum mechanics theory and the method of elasticity theory and structural mechanics-related displacement solution.Be full advantage of this effective mathematical tool-MATLAB, it can obtain the compounding elastic constitutive relation、compounding elastic modulus、compounding axis direction compressive stiffness and the numerical solution of interfacial mechanics problems to the CFTC.(2) It can obtain the distribution function expression f1(x) and f2(y) of the CFTC of the interfacial normal force. The images can conveniently describe the distribution of the confining force .The images show that the distribution of the rectangular section and square section CFTC of the interfacial normal force is uneven(it shows a shape of conic similarly), the distribution of rectangular section is more uneven than the square section.There is a phenomenon of stress concentration in the corner office.The confining force is maximum in the corner and least in the midpoint.The confining effect of square section CFTC is more than the rectangular section’s.(3) The paper study the variation of compounding elastic modulus, which increased obviously with the increase of steel ratio, increased slightly with the increase of strength grade of concrete.The study also shows that the compounding elastic modulus of rectangular section CFTC is slightly smaller than the square section’s in the same steel ratioρwhen when a/b≤2.4,and the difference at 5%. This conclusion is consistent with the literature[12].(4) The results show that the compounding elastic modulus and the ompounding axis direction compressive stiffnes of CFTC is higher than the conversion elastic modulus and the conversion axial stiffness without considering the confining effect,the compounding elastic modulus is higher than the conversion elastic modulus 1.36%-15.3% and the ompounding axis direction compressive stiffnes is higher than the conversion axial stiffness 1.55%-20.1% in the range of calculating.更多还原