火灾作用下钢管混凝土柱接触热阻非线性模型研究

发布时间：2018-01-15 11:04

本文关键词：火灾作用下钢管混凝土柱接触热阻非线性模型研究　出处：《西南科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着钢管混凝土柱在高层和超高层建筑的广泛应用,以及高层和超高层建筑火灾带来的巨大损失和危害,其在火灾作用下的温度及位移响应也受到越来越多的关注。钢管混凝土柱由于钢管与混凝土之间接触不紧密,在火灾作用下将产生接触热阻,接触热阻的存在将影响钢管混凝土柱在火灾下的温度响应和位移响应。因此研究钢管混凝土柱接触热阻非线性变化影响因素,建立接触热阻非线性模型,对于研究钢管混凝土柱火灾高温作用下的准确温度响应和位移响应有着重要意义。本文将从以下几个方面对钢管混凝土柱接触热阻非线性模型进行研究:(1)考虑了初始间隙、界面温度、以及钢管与混凝土黑度等多种因素的影响,利用传热学基本理论建立了高温作用下钢管混凝土柱接触热阻非线性理论模型,并通过钢管混凝土柱实际高温荷载试验测得曲线进行验证,验证了该理论的真实合理性。(2)选择合适的有限元模型,确定材料的热工参数及边界条件后引入钢管混凝土柱接触热阻非线性模型对火灾高温作用下的钢管混凝土柱进行热分析,得到钢管混凝土柱温度场分布,与钢管混凝土柱实际高温荷载试验进行验证,得到了火灾高温作用下钢管混凝土柱的准确的温度场分布。(3)在热分析的基础上,合理选择钢材、混凝土的本构模型,对其进行热-力耦合分析,得到钢管混凝土柱在火灾高温作用下的应力场及应变场响应。
[Abstract]:With the wide application of concrete-filled steel tubular columns in high-rise and super-high-rise buildings, the fire of high-rise and super-high-rise buildings has caused great losses and hazards. More and more attention has been paid to the temperature and displacement response of CFST columns under fire. Because the contact between CFST and concrete is not close contact thermal resistance will be generated under fire. The existence of contact thermal resistance will affect the temperature response and displacement response of concrete-filled steel tubular columns under fire. Therefore, the nonlinear influence factors of contact thermal resistance of concrete-filled steel tubular columns are studied, and the nonlinear contact thermal resistance model is established. It is of great significance to study the accurate temperature response and displacement response of concrete-filled steel tubular columns under fire temperature. In this paper, the nonlinear model of contact thermal resistance of concrete-filled steel tubular columns is studied from the following aspects: 1). The initial gap is considered. Based on the basic theory of heat transfer, the nonlinear model of contact thermal resistance of concrete filled steel tubular column under high temperature is established by the influence of interface temperature and blackness of steel tube and concrete. And through the actual high temperature load test curve of CFST column to verify the true rationality of the theory. 2) choose the appropriate finite element model. After determining the thermal parameters and boundary conditions of the material, the contact thermal resistance nonlinear model of concrete-filled steel tubular columns is introduced to analyze the thermal properties of concrete-filled steel tubular columns under fire and high temperature, and the temperature field distribution of concrete filled steel tubular columns is obtained. Verified by the actual high temperature load test of CFST columns, the accurate temperature field distribution of CFST columns under fire and high temperature is obtained. On the basis of thermal analysis, reasonable selection of steel is obtained. The constitutive model of concrete is analyzed by thermal-mechanical coupling, and the stress and strain field responses of concrete-filled steel tubular columns under fire and high temperature are obtained.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU398.9

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