Study On Residual Bearing Capacity Of Lattice Column After Lateral Impact Under Preloading Axial Force

With the advantages of good economic benefits and simple installation,lattice steel columns are widely used in the main load-bearing parts of industrial plant bent columns,structural support columns,tower cranes and so on.In the process of using,it is inevitable to suffer the impact of external objects.Lightly,it causes structural damage,and seriously leads to the overall collapse of the building,resulting in casualties and irreparable losses.Therefore,it is necessary to study the dynamic response and residual bearing capacity of latticed steel columns after lateral impact.The main research contents of this paper are as follows.The latticed steel column with the total length of 1440 mm is taken as the research object,and the finite element software ABAQUS is used to establish the model.The dynamic response and residual bearing capacity of the latticed steel column after impact are calculated and analyzed.The calculated results are compared with the existing lateral impact test and axial static load test results of the latticed steel column.The local and overall deformation,internal force and residual bearing capacity of the component are in good agreement.Combined with practical engineering,latticed steel columns are inevitably subjected to lateral impact of external objects when subjected to axial precompression axial force in the course of use.For latticed steel columns under different preloading axial forces,the lateral eccentric impact and axial static load finite element calculation and analysis are carried out to study the local and overall damage deformation,internal force distribution and residual bearing capacity of the structure under different preloading axial forces.The conclusions are as follows :Under the action of preloading axial force,through the calculation and analysis of the latticed steel column,the stress distribution nephogram of the specimen was obtained.With the increase of preloading axial force,the axial force of the specimen increased,but the structure of the specimen did not show obvious deformation.The impact force time history curve,local deformation and overall deformation of lattice steel column under lateral eccentric impact are recorded.By changing the preload value,the failure mode and internal force distribution of the component after lateral impact under different preload axial forces are obtained.With the increase of precompression axial force,the impact failure mode of lattice steel column structure decreases slightly,and the flexural value of impact point decreases gradually.The increase of precompression axial force increases the impact resistance of lattice steel columns.The change of preloading axial force has no significant effect on the impact duration,peak impact force and impact force platform value of the specimen;Under axial static load,the failure mode,residual deformation and time curve of residual bearing capacity are obtained.In the axial compression static load analysis of G-1 group of latticed steel column members with zero precompression axial force,serious instability failure occurs at the lateral impact position,and the buckling deformation direction is the drop hammer impact direction,showing the overall ‘ V ’ type failure.The buckling deformation direction of G-2,G-3 and G-4 groups with precompression axial force not zero is the opposite direction of drop hammer impact,and the whole component presents inverte “V” type failure.The influence of different precompression axial force on the residual bearing capacity of the component: With the increase of precompression axial force in a certain range,the axial ultimate bearing capacity of the component increases gradually.The increase of precompression axial force enhances the impact resistance of lattice steel columns.