PVA-ECC受拉构件计算理论及有限元分析
发布时间：2018-08-31 14:07
【摘要】：聚乙烯醇纤维增韧水泥基复合材料（Polyvinyl alcohol Fiber-Engineered CementitiousComposites简称PVA-ECC）是一种拉伸变形性能优异的水泥基复合材料，是通过断裂力学和微观力学原理对材料体系进行系统设计和优化得到的复合材料。PVA-ECC以其高韧性、耐冲切、耐腐蚀等优点引起纤维混凝土领域的广泛关注，国内外许多学者和研究人员对PVA-ECC多项力学性能进行了研究，尤其是其抗压性能和抗拉性能，也取得了一系列丰硕的结果，在自身实验基础上，得到了受压和受拉应力应变曲线。但其结果都是建立在各自实验环境、实验因素的基础上，给该种材料的广泛工程设计和工程应用带来阻碍。PVA-ECC材料的本构关系是进行结构非线性有限元分析和研究其设计理论的基础。 针对PVA-ECC具有优越的拉伸应变硬化特性，本文首先回顾了PVA纤维增强水泥基复合材料的研究进展，并重点讲述了PVA-ECC在单轴拉伸性能方面的研究成果，对其单轴拉伸应力-应变曲线进行归纳总结，得到具有代表性的PVA-ECC受拉应力-应变曲线，在此基础上，对配筋PVA-ECC受拉构件进行力学分析，推导出对应的承载力公式；并采用截面条带法对PVA-ECC受拉构件进行数值分析；为了验证承载力公式的正确性，基于ABAQUS，建立不同偏心距的配筋PVA-ECC受拉构件有限元模型，将有限元结果和理论结果进行对比分析，成果如下： 1、归纳和总结国内外关于PVA-ECC轴向拉伸试验的研究成果，PVA-ECC的单轴拉伸应力-应变曲线可分为单线性应变硬化曲线和双线性应变硬化曲线，本文采用origin软件对其进行拟合，表明了单线性应变硬化模型和双线性应变硬化模型可以很好描述PVA-ECC的单轴拉伸应力-应变曲线。 2、采用PVA-ECC单线型应变硬化模型，通过力学分析方法,对配筋矩形截面的PVA-ECC轴心受拉构件受力全过程进行了分析,以平截面假设为基础，结合变形协调方程和物理方程，经过严格的数学推导，得出轴心受拉过程中三个阶段的承载力公式。 3、采用同样的假设，，对配筋矩形截面的PVA-ECC偏心受拉构件受力全过程进行力学分析,经过严格的数学推导，得到小偏心受拉构件三个阶段的承载力公式和大偏心受拉构件三种破坏形态的承载力公式。以一具体的配筋PVA-ECC受拉构件为例，作出构件的极限承载力M-N曲线，全面反映了PVA-ECC构件的极限承载力变化状况。 4、基于截面条带法对PVA-ECC受拉构件进行数值分析，得到配筋PVA-ECC受拉构件的M-N曲线，并和理论推导结果进行对比。 5、基于ABAQUS有限元软件，建立不同偏心距的配筋PVA-ECC受拉构件的有限元模型，将有限元结果和理论推导结果进行对比分析，验证理论结果的正确性。
[Abstract]:Polyvinyl alcohol fiber toughened cement matrix composite (Polyvinyl alcohol Fiber-Engineered CementitiousComposites) is a kind of cement matrix composite with excellent tensile and deformation properties. PVA-ECC, which is obtained by the systematic design and optimization of the material system through fracture mechanics and micromechanics, has attracted wide attention in the field of fiber reinforced concrete because of its high toughness, punching resistance, corrosion resistance and so on. Many scholars and researchers at home and abroad have studied the mechanical properties of PVA-ECC, especially its compressive and tensile properties, and have obtained a series of fruitful results. On the basis of their own experiments, the stress-strain curves under compression and tension have been obtained. But the results are based on their own experimental environments, experimental factors, The constitutive relation of PVA-ECC material is the foundation of nonlinear finite element analysis of structure and the study of its design theory, which hinders the extensive engineering design and engineering application of this kind of material. In view of the excellent tensile strain hardening properties of PVA-ECC, this paper reviews the research progress of PVA fiber reinforced cement matrix composites, and focuses on the research results of uniaxial tensile properties of PVA-ECC. The stress-strain curve of uniaxial tension is summarized and the representative stress-strain curve of PVA-ECC is obtained. On the basis of this the mechanical analysis of the tensile members of reinforced PVA-ECC is carried out and the corresponding bearing capacity formula is deduced. In order to verify the correctness of bearing capacity formula, the finite element model of PVA-ECC tensile members with different eccentricity is established based on ABAQUS, and the finite element results and theoretical results are compared and analyzed. The results are as follows: 1. The uniaxial stress-strain curves of PVA-ECC can be divided into single linear strain hardening curve and bilinear strain hardening curve. In this paper, origin software is used to fit the strain hardening model. It is shown that the single linear strain hardening model and the bilinear strain hardening model can well describe the uniaxial stress-strain curve of PVA-ECC. 2. PVA-ECC unilinear strain hardening model is used. Based on the assumption of plane section and combined with deformation coordination equation and physical equation, the whole process of PVA-ECC axial tensile members with reinforced rectangular section is analyzed by means of mechanical analysis. The bearing capacity formula of three stages in the process of axial tension is obtained. 3. By using the same assumption, the mechanical analysis of PVA-ECC eccentric tensile members with rectangular section is carried out, and the strict mathematical derivation is given. The bearing capacity formulas of three stages of small eccentricity tensile members and three failure modes of large eccentricity tensile members are obtained. Taking a concrete reinforced PVA-ECC tensile member as an example, the M-N curve of the ultimate bearing capacity of the member is made, which reflects the variation of the ultimate bearing capacity of the PVA-ECC member. 4. Based on the section strip method, the PVA-ECC tensile member is numerically analyzed. The M-N curves of reinforced PVA-ECC tensile members are obtained and compared with the theoretical results. 5. Based on ABAQUS finite element software, the finite element model of reinforced PVA-ECC tensile members with different eccentricity is established. The finite element results are compared with the theoretical results to verify the correctness of the theoretical results.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528
[Abstract]:Polyvinyl alcohol fiber toughened cement matrix composite (Polyvinyl alcohol Fiber-Engineered CementitiousComposites) is a kind of cement matrix composite with excellent tensile and deformation properties. PVA-ECC, which is obtained by the systematic design and optimization of the material system through fracture mechanics and micromechanics, has attracted wide attention in the field of fiber reinforced concrete because of its high toughness, punching resistance, corrosion resistance and so on. Many scholars and researchers at home and abroad have studied the mechanical properties of PVA-ECC, especially its compressive and tensile properties, and have obtained a series of fruitful results. On the basis of their own experiments, the stress-strain curves under compression and tension have been obtained. But the results are based on their own experimental environments, experimental factors, The constitutive relation of PVA-ECC material is the foundation of nonlinear finite element analysis of structure and the study of its design theory, which hinders the extensive engineering design and engineering application of this kind of material. In view of the excellent tensile strain hardening properties of PVA-ECC, this paper reviews the research progress of PVA fiber reinforced cement matrix composites, and focuses on the research results of uniaxial tensile properties of PVA-ECC. The stress-strain curve of uniaxial tension is summarized and the representative stress-strain curve of PVA-ECC is obtained. On the basis of this the mechanical analysis of the tensile members of reinforced PVA-ECC is carried out and the corresponding bearing capacity formula is deduced. In order to verify the correctness of bearing capacity formula, the finite element model of PVA-ECC tensile members with different eccentricity is established based on ABAQUS, and the finite element results and theoretical results are compared and analyzed. The results are as follows: 1. The uniaxial stress-strain curves of PVA-ECC can be divided into single linear strain hardening curve and bilinear strain hardening curve. In this paper, origin software is used to fit the strain hardening model. It is shown that the single linear strain hardening model and the bilinear strain hardening model can well describe the uniaxial stress-strain curve of PVA-ECC. 2. PVA-ECC unilinear strain hardening model is used. Based on the assumption of plane section and combined with deformation coordination equation and physical equation, the whole process of PVA-ECC axial tensile members with reinforced rectangular section is analyzed by means of mechanical analysis. The bearing capacity formula of three stages in the process of axial tension is obtained. 3. By using the same assumption, the mechanical analysis of PVA-ECC eccentric tensile members with rectangular section is carried out, and the strict mathematical derivation is given. The bearing capacity formulas of three stages of small eccentricity tensile members and three failure modes of large eccentricity tensile members are obtained. Taking a concrete reinforced PVA-ECC tensile member as an example, the M-N curve of the ultimate bearing capacity of the member is made, which reflects the variation of the ultimate bearing capacity of the PVA-ECC member. 4. Based on the section strip method, the PVA-ECC tensile member is numerically analyzed. The M-N curves of reinforced PVA-ECC tensile members are obtained and compared with the theoretical results. 5. Based on ABAQUS finite element software, the finite element model of reinforced PVA-ECC tensile members with different eccentricity is established. The finite element results are compared with the theoretical results to verify the correctness of the theoretical results.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528
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