| When concrete go through high temperature,its mechanical property have obvious difference,because the component of concrete thick and thin ingredient,have different thermal performance and complicated physicochemical impact of ingredient.The concrete structure in the normal use phase of the environment is relatively large,especially in the cold and dry climate,and the mechanical properties of the material after the high temperature fire are more complex.The research method of this article by means of composite material mechanics and fracture mechanics of concrete,the experimental study and finite element numerical simulation based on the deterioration of our province and the working mechanism of concrete materials in high temperature mechanical properties after fire revealed.There are the main research contents:1.A large number of domestic and foreign literature on the fire of concrete is collected and summarized,and the thermal and thermodynamic properties of concrete materials after high temperature are systematically summarized.2.It studied the mechanical properties of concrete under different temperatures,different cooling modes and different static time and the constitutive model of concrete under uniaxial compression is established.3.Regression analysis was carried out according to the experimental data fitted the dimensionless ultimate compressive strength,peak strain,stres s-strain,initial elastic modulus Splitting strength and other mechanical properties with temperature,cooling,standing time of the coupling relation between type.4.On the basis of the experiment,the thermal parameters have been obtained,with the help of finite element software ANSYS,The concrete was simulated by FEM under different high temperature degrees of the temperature field and thermal structure coupled stress,and it describes further the performance of the material through the temperature of concrete in the high temperature field distribution,temperature stress distribution,compressive displacement and the compressive stress nephogram.This research aims to provide a more realistic calculation model and experimental parameters for the design and analysis of the concrete structure,and the fire resistance design,the repair and reinforcement after fire. |
