钢管混凝土构件抗扭承载力有限元模拟及实用算法研究

发布时间：2018-06-26 09:20

本文选题：钢管混凝土 + 有限元分析　；参考：《福建农林大学》2015年硕士论文

【摘要】：目前对钢管混凝土结构的研究大多集中于轴压、偏压(压弯)和纯弯受力状态下的力学研究,仅有少量文献涉及到钢管混凝土抗扭性能的研究,且无规范给出可供工程界应用的钢管混凝土抗扭极限承载力的计算公式。随着建筑结构跨度的不断增加以及建筑物结构形式多样化的不断发展,研究建筑物抗扭性能显得尤为重要。本文以圆形钢管混凝土构件为研究对象,进行了有限元模拟,并提出了钢管混凝土抗扭承载力实用算法。本文的主要研究内容、结果和结论如下：(1)通过有限元法建立基准有限元模型,对已有钢管混凝土受扭构件进行了有限元模拟和工作机理的分析,分析结果表明约束扭转和自由扭转下的扭转性能有所不同,在长细比较大时,差别不明显,当长细比较小时,由于固定端约束扭转剪切应力的影响,约束扭转下的抗扭承载力要大于自由扭转下的抗扭承载力,因此约束扭转下,长细比对抗扭承载力的影响不容忽视。(2)系统性地进行了约束扭转状态下钢管混凝土抗扭性能的参数分析,考虑了钢管混凝土抗扭性能与含钢率、钢管强度、混凝土强度、长细比等因素的相关性问题,特别考虑了长细比变化对约束扭矩的影响,并引入了考虑约束扭转剪切效应的影响系数。(3)基于极限平衡理论和经典材料力学的塑性理论,对试验数据和有限元分析数据进行分析拟合,提出约束扭转状态下钢管混凝土抗扭承载力的实用算法及适用条件,并将本文提出的实用算法与其他算法相比,结果表明,本文提出的抗扭极限承载力的计算结果精确度更高,数据离散性更小。(4)以抗扭承载力计算公式为基础,进行钢和混凝土扭矩分配比例的分析。分析结果表明,在扭转初期,由于钢管处于外缘,剪应力和剪应变都大于核心混凝土,外钢管所占扭矩比例比核心混凝土大。在扭转后期,由于混凝土的开裂受到外钢管的限制,产生螺旋效应,核心混凝土由单纯受扭变为压扭状态,由初期的受拉开裂变为了三向复合受力状态,大大提高了核心混凝土抗扭性能,而钢管由纯扭变为拉扭状态,扭矩提高值不大。
[Abstract]:At present, most of the researches on concrete-filled steel tubular structures are focused on the mechanical research under axial compression, partial compression (bending) and pure bending, and only a small amount of literature is concerned with the torsional behavior of concrete-filled steel tubular (CFST). The formulas for calculating the torsional ultimate bearing capacity of concrete filled steel tubular (CFST) are given in this paper. With the continuous increase of the span of the building structure and the continuous development of the diversification of the building structure, it is particularly important to study the torsional behavior of the building. In this paper, the circular concrete-filled steel tube members are taken as the research object, the finite element simulation is carried out, and a practical algorithm for torsional bearing capacity of concrete filled steel tubular member is proposed. The main contents, results and conclusions of this paper are as follows: (1) the basic finite element model is established by finite element method, and the finite element simulation and working mechanism analysis of existing concrete filled steel tubular torsional members are carried out. The results show that the torsional behavior of restrained torsion is different from that of free torsion. When the length ratio is large, the difference is not obvious. When the fineness ratio is small, the torsional shear stress at the fixed end is affected by the constraint torsional shear stress. The torsional bearing capacity under restrained torsion is greater than that under free torsion, so under restrained torsion, The effect of aspect ratio on torsional bearing capacity can not be ignored. (2) the torsion resistance of concrete-filled steel tubular (CFST) under restrained torsion is systematically analyzed, and the torsion resistance of concrete-filled steel tube (CFST) and steel content, strength of steel tube, strength of concrete-filled steel tube are considered. In this paper, the influence of slenderness ratio on the constraint torque is considered, and the influence coefficient is introduced. (3) based on the limit equilibrium theory and the plastic theory of classical material mechanics, The experimental data and finite element analysis data are analyzed and fitted, and the practical algorithm and applicable conditions for torsional bearing capacity of concrete filled steel tube under constrained torsion state are proposed. The results show that the practical algorithm proposed in this paper is compared with other algorithms. The calculation results of torsional ultimate bearing capacity proposed in this paper are more accurate and the data dispersion is less. (4) based on the calculation formula of torsional bearing capacity, the torque distribution ratio of steel and concrete is analyzed. The results show that at the beginning of torsion, the shear stress and strain are larger than the core concrete due to the outer edge of the steel tube, and the proportion of torque of the outer steel tube is larger than that of the core concrete. In the late torsion period, the cracking of concrete is restricted by the outer steel pipe, and the spiral effect is produced. The core concrete changes from simple torsion to compression and torsion, and from the initial stage to the three-direction composite force state. The torsion resistance of the core concrete is greatly improved, while the steel pipe is changed from pure torsion to tension-torsional state, and the torque increase is not significant.
【学位授予单位】：福建农林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU398.9

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