Study On Dynamic Response And Damage Assessment Of H-shaped Steel Columns Under Impact

H-shaped steel columns may suffer from impact load during service.H-shaped steel column is the most important component of steel structure building.Its impact resistance is an important research topic in the field of civil protection engineering.In this paper,test,numerical simulation and simplified theoretical analysis are used to study the dynamic response,relevant design calculation and rapid assessment of H-shaped steel columns under horizontal impact.The main work is as follows:(1)A test device for horizontal impact is designed to realize the horizontal impact of H-shaped steel column.The influence of axial compression ratio and bending moment ratio is considered in the test.The holistic displacement and acceleration during the impact process are tested,and the strain at the key section is tested.At the same time,the local strain field evolution process at the impact location is tested by means of non-contact strain three-dimensional strain test.The influence mechanism of axial compression ratio on the dynamic response of H-shaped steel column is obtained.The development rule of displacement and the distribution of section bending moment are obtained.(2)The finite element model of H-shaped steel column is established by using the finite element software ABAQUS.The strain rate effect,the contact effect between hammer and steel column,bolt and end plate,bolt and steel column are considered.The coupling of impact load and axial static load is realized by implicit analysis and dynamic display analysis.Then the numerical simulation results are compared with the test data,and the results show that the numerical simulation results are in good agreement with the test data.(3)on the basis of the test,the stress development and failure mode of the impact process are further studied by numerical simulation method,and then the parametric analysis is carried out,including the axial compression ratio,impact mass,impact velocity,impact energy and impact location.The impact of each parameter on the impact time curve,displacement curve,impact force strengthening coefficient and energy absorption rate is analyzed The influences of impact velocity,impact mass and impact location on the development of the displacement of H-shaped steel columns are analyzed.(4)Based on the analysis of impact test and numerical simulation results,the difference of the holistic displacement field development process between symmetrical position impact and asymmetric position impact is obtained.The existing displacement field estimation formulas are optimized,and a displacement field estimation formula considering mass ratio,impact energy,impact position,column ultimate bending moment and other parameters is proposed,and the formula is compared with this experiment and numericalsimulation.Other scholars' experiments and the existing displacement field formulas are compared in all directions,and the error is less than 20%.(5)The residual carrying capacity test and the numerical simulation of the damaged h-shaped steel columns are carried out,and the influence of each parameter(impact velocity,impact mass,impact energy,impact position and axial compression ratio)on the remaining bearing capacity of the h-shaped steel column is analyzed.The relationship between the damage parameter(residual displacement and local buckling depth)and the residual bearing capacity is analyzed,the residual bearing capacity of the damaged component is preliminarily obtained,The numerical simulation results are used to build a database,and a rapid evaluation model of steel column damage is given based on the neural network algorithm.