The Analysis Of Temperature Field And Temperature Stress Of CFST Under Thermal Mechanical Coupling

Fire is one of the most frequently occurring and highly destructive disasters, which caused direct economic losses only after drought and floods, while the frequency of its occurrence is first among the various disasters. Especially in recent years, due to the factors of buildings become high-rise, large-scale and composite, fire is more frequent and its scale becomes larger.The fire of CFST research which is a branch of the fire is getting more attention.CFST is a new composite material which is formed by a thin wall of steel tube filled with concrete.CFTS has the advantages of high capacity, good ductility, toughness, easy construction, corrosion resistance, excellent corrosion resistance and high economic efficiency, which can be called as a high-quality, high-strength, economically reasonable member. So it is widely used in high-rise building construction and bridge structure. The excellent performance of CFST relies on the steel concrete composite action.In this paper, the simulation analysis of CFST to research mechanical properties and temperature stress under the situation of fire. Specific work is carried out in the following aspects:(1)The engineering application of concrete filled steel tube concrete features and characteristics and the square steel tube concrete filled steel tube.Summarize the results related to mechanical properties of steel and concrete thermal systematically, and on this basis to determine the appropriate steel and concrete thermal performance and mechanical properties at high temperatures.It determine a force-hot constitutive model for the steel and main concrete of CFST,and the model takes the interaction between the composition of concrete and steel pipe into account.(2)Introduces the general theory and analysis method of thermal coupling analysis theory, the temperature field of concrete steel tube column, the thermal parameters of steel and concrete were determined, and to select the reasonable method of coupling analysis.(3)The simulation model and theoretical analysis of this paper needs to be determined.Fire resistance of the model and reasonableness of this case needs to be verified. The finite element program ANSYS simulates the size of the column length L =1732mm, side B = 300 mm model to simulate a three-dimensional temperature field of CFST on the condition of each side with evenly fire. We only use the 1/4 model as the research object to simplify the calculation, so that the temperature distribution of steel and concrete can be observed conveniently.The paper has brought some help to study the performance characteristics and fire resistance of CFST with ANSYS in the future.