不均匀防火涂层对火灾条件下某简支钢梁温升和变形特性的影响

Effects of non-uniform fire protection coating on temperature distribution and deformation of a simply supported steel beam under fire conditions

在钢结构抗火研究中通常假设构件表面防火涂料涂刷均匀、厚度一致。但实际上这些涂层由于多种原因厚度并不一致,不均匀防火涂层可能对钢构件的温升特性和结构抗火性能产生影响。基于已被证实的不均匀防火涂层厚度服从正态分布的假设,运用有限元软件ANSYS分析了某简支钢梁在标准温升火灾条件下的温升和变形特性,研究结果表明:钢梁轴向温度不再一致,并呈区域分布,横截面温度呈非对称分布;涂层的不均匀性对轴向变形影响较小,但对构件挠度影响较大。标准差越大,其温度和挠度的相对误差越大。

Fire protection coating on the steel member＇s surface was generally assumed to be with a uniform thickness distribution. However, the coating may be non--uniform due to many factors, which might affect the fire safety of the steel member. In this paper, the FEM software ANSYS was used to analyze the differences in both surface temperature and deformation of a simply supported steel beam covered with various kinds of non--uniform fire coating under the validated consumption that fire coating thickness can be described as normal distribution normal distribution. The results indicate that the temperature is no longer uniform along the longitudinal direction of the steel beam, but shows regional distribution when the fire coating is non--uniform, and the temperature distribution of the cross section is no longer symmetry. At the same time, the non--uniform thickness of fire coating has little effect on the axial deformation but an obvious effect on the deflection of the steel beam. The standard deviation will affect the temperature distribution and deformation significantly, and a higher standard deviation will lead to a bigger relative error of temperature distribution and deformation.