预置裂缝对混凝土热量传输规律影响的试验研究与有限元分析

发布时间：2018-03-15 23:15

本文选题：受火试验　切入点：截面温度场　出处：《青岛理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：混凝土作为一种非匀质材料通常是带裂缝工作的,这种裂缝的存在为热量、水分、氯离子和CO2等介质的传输提供了更为便利的途径。然而大多数研究未考虑混凝土带裂缝工作这一客观事实,因此有必要对带裂缝混凝土结构的耐火性能进行研究。本文以“高温下带预置裂缝的素混凝土试件”为研究对象,通过在ISO834标准升温环境下加热零应力开裂混凝土试件试验,探寻高温下零应力开裂混凝土试件内部温度场的发展规律,为带裂缝钢筋混凝土构件抗火性能影响的研究提供理论基础。为研究裂缝宽度对火灾下混凝土热传递的影响,本文针对带预置裂缝的混凝土试件在火灾作用下的截面温度场变化规律进行了试验研究和数值分析,具体研究内容如下:(1)总结国内外关于钢筋混凝土结构抗火的研究现状,在分析现阶段火灾高温下钢筋混凝土结构研究所存在的问题和不足的基础上,提出本文的研究思路。(2)综合评述混凝土的热工性能及火灾温度发展过程,从而确定本文采用的热工参数。(3)本文设计了3个带预置裂缝的混凝土试件和1个完整对比试件,预置裂缝宽度w分别为0.5mm、1mm、3mm。通过试件在ISO834标准升温曲线下的明火试验,考察带裂缝截面上的温度分布并为数值分析提供数据支持。(4)按照火灾试验实际升温曲线,采用ANSYS有限元软件对试件截面进行温度场数值模拟,得出试件在高温下的截面温度场分布云图、温度-时间曲线等,探讨ANSYS有限元软件数值模拟混凝土结构高温性能的可行性和准确性。
[Abstract]:Concrete, as a non-homogeneous material, usually works with cracks that exist in heat, moisture, The transport of chloride ions and CO2 provides a more convenient way. However, most studies do not take into account the objective fact that concrete work with cracks. Therefore, it is necessary to study the fire resistance of concrete structures with cracks. In this paper, the "plain concrete specimens with preset cracks at high temperature" are taken as the research object, and the zero stress cracking concrete specimens are heated under the ISO834 standard temperature environment. In order to provide a theoretical basis for the study of the effect of crack width on the thermal transfer of concrete under fire, this paper explores the development of temperature field in the specimens with zero stress cracking at high temperature, which provides a theoretical basis for the study of the effect of crack width on the fire resistance of reinforced concrete members. In this paper, the variation of cross-section temperature field of concrete specimens with preset cracks under the action of fire is studied experimentally and numerically. The specific research contents are as follows: 1) summarizing the research status of fire resistance of reinforced concrete structures at home and abroad. On the basis of analyzing the existing problems and shortcomings of the research on reinforced concrete structures under fire and high temperature at present, the paper puts forward the research idea of this paper, and gives a comprehensive comment on the thermal properties of concrete and the development process of fire temperature. In this paper, three concrete specimens with preset cracks and one complete contrast specimen are designed. The width of the preset crack is 0.5mm / 1mm / 3 mm / m respectively. The open fire test of the specimen under the ISO834 standard heating curve is carried out. The temperature distribution on the section with cracks is investigated and the data for numerical analysis is provided. (4) according to the actual heating curve of the fire test, the temperature field of the specimen section is simulated by ANSYS finite element software. The temperature distribution cloud diagram and temperature-time curve of the specimen at high temperature are obtained, and the feasibility and accuracy of numerical simulation of high temperature performance of concrete structure with ANSYS finite element software are discussed.
【学位授予单位】：青岛理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528

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