Dynamic Response Of Partially Concrete Filled Steel Tubular Columns Under Rigid And Flexible Impact Load

Partially concrete filled steel tubular structure is a composite structure formed by filling concrete with a certain height in the steel pipe,applied in practical engineering owing to its good seismic and anti-impact performance.In recent years,load-bearing components is collided by a truck,leading to buildings,bridges damage or structural collapse and causing huge casualties and property loss.Therefore,it is significant to evaluate the impact damage of partially concrete filled steel tubular members in structural design and how to improve the impact resistance of components by using structural measures.Based on them,this paper studies the impact resistance of partially concrete filled steel tubular columns by using the drop hammer tester of Nanjing University of Technology,and uses ABAQUS to simulate the whole process of it under rigid and flexible impact.It can provide the necessary scientific basis of truck impact resistance.This paper mainly carried out the following research work:(1)The horizontal impact test of 8 partially concrete filled steel tubular columns was completed.Taking the effects of different concrete filling rate,impact velocity,boundary conditions into consideration,impact force,column top reaction force,impact point deflection,acceleration as well as external steel pipe strain-time curves were measured,and impact force-impact point displacement as well as column top reaction force-impact point displacement is analyzed.The time lag between reaction force and impact force is discussed.(2)Impact process of partially concrete filled steel tubular column under impact load was simulated by using ABAQUS nonlinear model,getting the failure mode and time-histories of impact force,impact point deflection,The finite element simulation results reveal the stress wave propagation process and the failure mechanism of the member under the horizontal impact load.(3)The failure mechanism of partially concrete filled steel tubular column is studied by using the scaled equivalent truck frame model,dynamic performance and failure mechanism under the impact of flexible and rigid impact are compared,and the parametric analysis of the flexible impact was carried out.And it can provide a reference for deep understanding of the dynamic performance under truck impact.