| In recent years, with the rapid development of economy, there are a lot of building damages and casualties caused by explosion load that certainly brings huge losses and unpredictable disasters. Steel structures have been widely used because of its many advantages. With increasing of the requirement for building materials and the development trend of construction of lightweight and high strength, high strength steel is gradually used in many buildings. The peak overpressure of the explosion loading is high and during time is short, the good plastic steel has obvious advantages, it plays an important role in the structure of anti-explosion as the main bearing components. The research on the dynamic response of high strength steel column under explosion load has necessary theoretical significance and practical significance.This paper uses fluid-structure interaction method of the show dynamic finite element software ANSYS/LS-DYNA to simulate the formation of the TNT explosion shock wave and characteristics of blast overpressure outdoor. A numerical simulation method for putting a TNT explosion shock wave overpressure as a line load along the column effect on steel column is put forward. The different pressure peak value and duration of the explosion load effect is put on the different position of the steel structure column. Dynamic response and failure modes of steel column are analysized under different case by using fluid-structure interaction and the equivalent triangle wave method. Through influence factors for dynamic response of H section high strength steel column under blast loading is analyzed, the major influence factors is put forward A reference basis for steel structure design is provided and the appropriate advice about width-to-thickness ratio is given.This paper uses LS-DYNA for much numerical simulation, the mode of transmission of shock wave and dynamic response analysis of high strength steel columns under explosion load, the main draw the following conclusion:(1) Large-scale finite element analysis software LS-DYNA can accurately simulate the dynamic response of a steel column and the transmission of explosion shock wave after selecting appropriate finite element model, material properties and calculation parameters.(2) The spread of explosion shock wave is a process that the propagation velocity is large, while the peak load is great but during time is very short. Scale distance is smaller, and shock wave propagation is faster. The steel column can damage due to blast shock wave flow around. The change law of the shock wave peak and impulse is different along the column under the close air explosion under different scale distance. The Reflection shock wave will increase the pressure in the column foot. The arrival time of shock wave gradually increase on both ends of column height.(3) The influence of axial compression ratio on the deformation and damage of the steel column is relatively obvious; the larger vertical load will increase deformation and damage of steel column under blast loading. When steel column constraint degree is high, the influence of axial compression ratio decrease rapidly, the increase of the constraint degree can effectively prevent deformation and destruction of steel column.(4) The column foot can be easily destroyed under low position of the explosive near the ground explosion, but the higher the explosive is adverse to bending resistance of steel column. When the scale distance is same and slenderness ratio is greater, displacement of the steel column is larger and more unstable. In the design of anti-explosion, reduce of the flange width and increase of the web width can well resist blast shock wave and avoid shear failure of column foot. |
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