Study On Impact Resistance Of H-shaped Steel Columns Sprayed Polyurea Elastomer

As the load-bearing member of steel structure,H-shaped steel column will inevitably suffer from various unexpected impact loads during use,which will cause local deformation damage of the structure and even collapse of the whole structure,causing serious influence on social life.It will inevitably suffer from various accidental impact loads during use,cause local deformation and damage,and even lead to the collapse of the entire structure,seriously affecting social life.In order to improve the impact resistance of H-shaped column,in this thesis took polyurea H-shaped steel column with different thickness as the research object,and studied the protective performance of H-shaped steel column composite structure under the action of lowspeed impact of falling hammer and high-speed impact of fragment group through numerical simulation method.The main work is as follows:(1)Numerical simulation was used to analyze the deformation damage of Hshaped steel column sprayed with different polyurea thickness under low speed impact.The results show that the failure mode of H-shaped steel column is global deformation,and there is local bending deformation at the impacted position,and the deformation of steel column can be reduced by spraying 5mm polyurea coating.The impact quality,impact velocity and axial compression ratio are studied.The results show that the impact duration increases with the increase of impact mass and axial compression ratio.The impact mass has little effect on the peak value of maximum impact force,but the peak value of maximum impact force decreases with the increase of axial compression ratio.The greater the impact velocity,the greater the peak value of the maximum impact force.(2)The residual bearing capacity of H-shaped steel column damaged by low-speed impact is calculated,and the load-displacement curves of H-steel column under different working conditions are drawn.The results show that polyurea coating can effectively improve the residual bearing capacity of the damaged specimens under axial compression: under different mass,the maximum residual bearing capacity increases by16.6%;At different speeds,the maximum residual bearing capacity is by 17.1%.Under different coaxial pressure ratio,the maximum residual bearing capacity is increased by17.3%.(3)Deformation and fracture of the H-shaped steel column are investigated by a group of fragments at high speed.It was found that the group of fragments penetrated mainly steel columns ang penetrated locally.By varing the thickness of the polyurea coating to analyze the protective effect of polyurea on the structure,the results show that spraying polyurea can significantly reduce the deformation and damage of Hshaped steel columns caused by flakes.With an increase in the thickness of the urea coating,the area of the penetration of the steel column by the group of fragments decreases.When the polyurea coating thickness increases to 7mm,the peak displacement in midspan decreases by 43.8% and the internal energy decreases by 80%.(4)The effects of various parameters on H-shaped steel columns sprayed with7 mm polyurea under the action of fragments were studied.The results show that the penetration failure of steel columns is not obviously affected by slenderness ratio under the same other conditions;With the same amount of steel,the thicker the flange,the less perforation and the smaller damage,but it is more prone to buckling instability;With the same explosive quantity,the greater the distance from the explosion center to the Hshaped steel column,the smaller the damage.