高温（火灾）作用后混凝土材料力学性能的试验研究及有限元分析

发布时间：2018-05-25 20:19

本文选题：高温混凝土 + 冷却方式　；参考：《吉林建筑大学》2017年硕士论文

【摘要】：混凝土结构在高温作用下,由于组成混凝土的粗细骨料和水泥等胶结材料的热工性不同,再加上其各组成成分间复杂的理化作用,使的混凝土力学性能差异很大。特别在我省寒冷干燥的气候条件下,混凝土结构在正常使用阶段下的环境差异就较大,则对其在遭受高温火灾后所表现出来的材料力学性能就更为复杂。本文借助于复合材料力学和混凝土断裂力学的研究手段,以试验研究和有限元数值模拟为基础,揭示了我省混凝土材料在高温火灾作用后力学性能的劣化规律及工作机理。其主要研究内容如下:1.搜集整理了国内外关于混凝土火灾方面的大量文献资料,对混凝土材料在高温过火后的热工性和热力学性能进行了系统的概括和总结。2.研究了混凝土材料在不同温度、不同冷却方式、不同静置时间作用下的抗压强度变化情况,建立了高温后混凝土单轴受压的本构关系模型。3.根据试验数据进行回归分析,拟合出了无量纲下的抗压强度、应力-应变、初始弹性模量、劈裂强度等力学性能参数与温度、冷却方式、静置时间之间的耦合关系式。4.在试验的基础上,利用已得出的热工参数,借助于ANSYS有限元计算软件,对混凝土在不同高温下的温度场和热-结构耦合场进行了有限元数值模拟,并通过混凝土在高温下温度场分布、温度应力分布、抗压位移云图、抗压应力云图等对其材料性能做了进一步的阐述。本课题的研究力求为本省混凝土结构设计分析,以及抗火设计、火灾后的修复加固等提供更符合实际的计算模型和试验参数。
[Abstract]:Under the action of high temperature, the mechanical properties of concrete are greatly different due to the different thermal properties of the coarse aggregate and cement, and the complex physical and chemical action among the components. Especially in the cold and dry climate of our province, the environmental difference of concrete structure in the normal service stage is great, and the mechanical properties of the concrete structure after the high temperature fire are more complex. By means of composite mechanics and fracture mechanics of concrete, based on experimental research and finite element numerical simulation, this paper reveals the deterioration law and working mechanism of mechanical properties of concrete materials in our province after high temperature fire. The main research contents are as follows: 1: 1. A great deal of literature about concrete fire is collected and sorted out, and the thermal and thermodynamic properties of concrete after high temperature overfire are summarized and summarized systematically. The change of compressive strength of concrete under different temperature, different cooling methods and different static time is studied, and the constitutive relation model of uniaxial compression of concrete under high temperature is established. On the basis of regression analysis of test data, the coupling relationship between mechanical properties such as compressive strength, stress-strain, initial elastic modulus, splitting strength, temperature, cooling mode and static time is obtained. On the basis of the experiment, the temperature field and thermal-structure coupling field of concrete at different high temperatures are simulated by using the obtained thermal parameters and the finite element calculation software ANSYS. The material properties of concrete are further expounded through temperature field distribution, temperature stress distribution, compression displacement cloud diagram, compressive stress cloud diagram and so on. The research of this subject aims to provide more practical calculation model and test parameters for the design and analysis of concrete structure in this province, as well as for the design of fire resistance, repair and reinforcement after fire.
【学位授予单位】：吉林建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

【相似文献】