Mechanical Properties Of Composite Cellular Beam At High Temperature

The composite cellular beam is composed of cellular beams and concrete slabs made in the factory through shear connectors,which is a kind of composite structure.The honeycomb composite beams not only have the advantages of good flexural performance of honeycomb beams,but also have the advantages of good compressive performance of concrete floor slabs.By connecting the two beams,the shortcomings of easy compressive instability of steel structures and poor tensile performance of concrete are avoided.And honeycomb beams and concrete floors can be prefabricated in factories,which is in line with the current trend of vigorously promoting assembly building in China.Although there are many advantages of steel structure,the mechanical properties of steel structure will decline sharply at high temperature,which will lead to the destruction of steel structure buildings.Therefore,it is necessary to study the mechanical properties of honeycomb composite beams at high temperature.By using the method of experimental research and computer numerical simulation analysis,the effects of a series of factors on the mechanical properties of honeycomb composite beams at high temperature,such as opening ratio,hole spacing,web thickness,stiffening rib setting and external load,are comprehensively studied,which is helpful to provide data and reference for national,local and industrial codes,and to improve the practical application of honeycomb composite beams.Safety performance,which is conducive to the promotion and use of honeycomb composite beams,can also reduce or avoid casualties and property losses in building fires.In order to study the mechanical properties of honeycomb composite beams under high temperature,the temperature field distribution,stress characteristics,failure modes and fire resistance limit of honeycomb composite beams during heating process are analyzed by means of experimental research and computer numerical simulation analysis.In the experiment,the solid-web honeycomb composite beams were used as the control group.The failure modes of circular-hole honeycomb composite beams and hexagonal-hole honeycomb composite beams under actual fire were compared to analyze the effects of various parameters on the mechanical properties of honeycomb composite beams at high temperature.Using numerical simulation method and ABAQUS software,the temperature field distribution of honeycomb composite beams is simulated,and the temperature distribution law of the beams and concrete slabs during the heating process is obtained.The relationship between mechanical properties of honeycomb composite beams under high temperature is determined by changing the opening ratio,hole spacing,hole shape,web thickness,stiffening rib and external load.The results show that the spacing of holes has little effect on the mechanical properties of honeycomb composite beams at elevated temperatures when the opening ratio is unchanged;the opening ratio has little effect on the mechanical properties of honeycomb composite beams at elevated temperatures within a certain range,but when the opening ratio is too large,the performance of beams will be seriously reduced by the weakening of the cross section;the setting of stiffeners can effectively extend the honeycomb composite beams.The fire resistance limit of the beam prevents the buckling of the lower flange flange flange and web caused by the degradation of the mechanical properties of the steel beam;the increase of web thickness will help to ensure the local stability of the web,but will not contribute much to the critical temperature and bearing capacity of the honeycomb composite beam,and the increase of web thickness in practical application is not conducive to cost savings;the magnitude of load affects the mechanics of the honeycomb composite beam at high temperature.An important factor in performance.The above research results can lay a foundation for further research on fire resistance of honeycomb steel structures.