| In recent years,with the rapid development of the economy,the number of vehicles and urban infrastructure grows with each passing day.The accident that the building structure is subjected to the vehicle accident collision in its service period occurs so often.Then,the building structure is often damaged or even collapsed with the influence of load effect,which poses a serious threat to social security,and the anti-collapse performance of building structures has become a essential factor that structural engineers must consider when designing.Due to the good mechanical properties,concrete-filled steel tube structures are widely used in bridge building and high-rise building structure.As the main stress component of the structure,the anti-impact capability of the column will be the key to the safety of the whole building structure.Therefore,it is of great theoretical and practical significance to study the dynamic response and damage analysis of concrete-filled steel tubular piers under vehicle impact load.In this paper,the finite element program ANSYS/LS-DYNA is used to analyze the dynamic response and damage of concrete-filled steel tubular piers under the impact load of vehicles.Then,based on the damage criterion of support Angle,the damage curve is preliminarily established through a large number of numerical simulation,and the damage curve formula is finally fitted.The specific research work and results are as follows:(1)The finite element simulation of three groups of related tests was carried out through the finite element program ANSYS/LS-DYNA,and the simulation values of impact time history curve and displacement time history curve under various working conditions were obtained respectively,the finite element simulation of three groups of related tests was carried out through the finite element program ANSYS/LS-DYNA,and the simulation values of impact time history curve and displacement time history curve under various working conditions were obtained respectively.Then compared with the test values,the results show that the physical deformation,impact force and displacement of the members are in good agreement with each other,which verifies the applicability and reliability of the finite element software and numerical model used in the finite element simulation analysis of the dynamic response of concrete-filled steel tubular column under impact load.(2)The finite element model of concrete filled steel tube(CFST)pier for vehicle impact is established and its parameters are analyzed.It shows that the overall trend of the impact time history curve can be basically divided into three stages: sudden change,stability and decline.However,when the vehicle speed or vehicle mass increases to a certain value,a second mutation will occur,forming four stages of mutation,stability,re-mutation and decline.The secondary mutation value increases with the increase of vehicle speed or vehicle mass.According to the time history curve of impact force obtained by parameter analysis,the local average method and the global average method are respectively adopted to calculate the equivalent impact force.The results show that the value of vehicle impact force in the relevant codes of our country is slightly unsafe.(3)The damage assessment of concrete-filled steel tube pier under vehicle impact load is preliminarily discussed.Through numerical analysis and calculation,it is found that under the effect of vehicle impact load,Concrete-filled steel tube piers mainly damaged by bending and shearing.Then,according to the damage condition of concrete-filled steel tube pier obtained by simulation,the damage criterion based on the Angle of bearing is determined,the damage curve is established according to the damage criterion,and the formula of the damage curve is finally fitted out.The damage degree of concrete-filled steel tube piers under vehicle impact load can be rapidly evaluated according to the regional position of the composite points of vehicle mass and velocity in the damage curve. |
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