Bending And Natural Viberation Analysis Of Triangular Cone Grid Under High Temperature

Grid structure is mainly used in large space steel structure buildings,The main structural material is steel,But the fire resistance of steel is poor,Finally,it led to the overall collapse.Causing irreparable casualties and property losses.Therefore,it is of great significance to study the bending and vibration of grid structures under fire.At present,the research on the bending and vibration of grid structures at roo temperature is relatively mature,but the bending and vibration analysis of grid structures at higtemperature is relatively less.Therefore,based on the existing literature and research results at home and abroad,this paper analyzes the bending and vibration of triangular cone grid under high temperature.The main research contents are as follows:(1)This paper introduces the temperature rise curve of large space grid structure under fire,and considers the influence of heat convection,heat radiation and heat conduction.The calculation method of temperature rising stage under high temperature of fire is summarized and explained.(2)On the basis of considering the change of material parameters under high temperature of fire,the bending and natural vibration of triangular cone grid under high temperature are analyzed based on the idea of decomposition stiffness,and the calculation formulas of deflection,internal force and natural vibration frequency of three-dimensional grid under high temperature are summarized.The deflection,internal force and fundamental frequency of triangular cone grid with different sizes and simply supported on four sides are analyzed.(3)The finite element analysis software is used to simulate the heating process of triangular cone grid structure under the joint action of external load and fire high temperature.The variation of deflection,internal force and fundamental frequency with temperature of different sizes of grid structure is analyzed,and the theoretical formula calculation results and simulation results are compared and analyzed.The applicability of the modified formula of deflection,internal force and natural vibration frequency of triangular cone grid under high temperature is verified.