Study On Damage And Protection Technology Of H-Section Steel Columns Subjected To The Synergistic Effects Of Vehicle Impact And Blast

In order to investigate the anti-knock and anti-blast performance of H-section steel column under the synergistic effect of vehicle impact and blast.The difference of damage and dynamic response of H-section steel columns under three working conditions of vehicle impact,blast load and combined impact and blast load are compared and researched based on the finite element software for nonlinear analysis ANSYS/ LS-DYNA.Meanwhile,the influence of steel column design parameters and external load factors on the damage effect of H-section steel column under the synergistic effects is investigated by parametric analysis method.And put forward a more effective protective measures against the synergistic effect.The main research work and results of this paper are as follows:(1)This paper completely establishes the whole process model of the explosion after the automobile first impacts the steel column,which is composed of five parts: automobile,steel column,explosive,air and rigid ground.By comparing the simulation and experimental results of steel column drop hammer impact text and steel column explosion test,the correctness of the coupling algorithm,contact type and material model used in the modeling process is indirectly proved.(2)The differences of dynamic response of H-shaped steel columns under three kinds of load conditions,namely,the impact of vehicle impact alone,the blast load alone and the synergistic effect of the above two are compared and analyzed.research shows: The local damage caused by the impact of the vehicle is obvious,and the overall damage is small.The overall damage caused by the blast wave is large,and the global damage is evenly distributed(3)The influence of the self design factors of the steel column on the dynamic response and damage of the steel column under the synergistic effect is explored.Research shows: Properly increasing the strength can improve the anti-knock and anti-blast performance of the steel column,but it cannot be blindly improved.The effect of changing the slenderness ratio of the column on its overall anti-knock and anti-blast performance is not obvious.The anti-knock and anti-blast performance of circular hollow section steel column is the best,the H-section steel column is the second,Square hollow section is the worst and has a large gap with the front two.Under the premise of flange thickness,web thickness,column height and steel volume,the narrow flange section steel column has stronger resistance to the synergistic effect.(4)The influence of external load factors on the dynamic response and damage of steel columns under the synergistic effect are investigated.Research shows: In order to ensure the anti-knock and anti-blast performance of the H-section steel column,when the steel strength grade is Q390,the axial pressure ratio should be controlled within 0.4.When the vehicle is impacted laterally,the bending and torsion effects of the steel column under the synergistic effect are most serious when the lateral offset of 500 mm.The overall damage effect of the steel column increases with the increase of the explosive charge.The damage effect of the steel column is aggravated with the decrease of the explosion distance,and when the distance is less than 2.1m,the damage effect increases sharply.(5)This paper proposes a more effective protective technical measure against the synergistic effect.Research shows: The protective effect of the three rubber cushion layers of square holes,round holes and solid sections is basically the same.When the thickness of the rubber cushion of the protective structure is 80 mm,the overall displacement of the steel column is at a relatively low value.When the height of the protective structure is 2.4m or 2.7m,the overall displacement of the steel column is at a relatively low value.