Numerical Study On Anti-explosion Performance And Protection Of UHPCFDST Column Under Near Explosion

Since the 21 st century,the frequent occurrence of explosion terrorist attacks and explosion accidents have all sounded the alarm for us,strengthening the anti-explosive performance of building structure load-bearing columns,seeking safer explosion-proof structures and protective measures have become urgent,and the hollow interlayer is super high Ultra-high Performance Concrete-filled Double Skin Steel Tubes(UHPCFDST),as a new type of steel-concrete components,perfectly combine hollow-filled double skin steel tube(CFDST)and super The advantages of both Ultra-High Performance Concrete(UHPC)have the characteristics of sufficient strength,good ductility,excellent energy absorption and crack resistance.It is precisely because of these excellent properties that it becomes an upgrade The ideal structure of anti-explosion structural members.As an energy dissipation structure,the foam aluminum sandwich panel has excellent mechanical properties such as low relative density,high specific modulus,high specific strength and good energy absorption buffer effect.It is very useful in the anti-explosion protection of structural load-bearing columns.Great engineering significance.In order to study the anti-explosion performance of UHPCFDST column under near-blast load and the protective effect of aluminum foam sandwich panel on UHPCFDST column under near-blast,a three-dimensional finite element model of TNT explosive-UHPCFDST column-air was established,and ALE multi-material fluid Coupling algorithm,from the five aspects of UHPCFDST column dynamic response,damage mechanism,energy absorption characteristics,impact parameter research and protective performance of aluminum foam sandwich panel under near explosion,the calculation results show that:(1)The main deformation modes of UHPCFDST columns under near-blasting are local depression deformation and overall lateral displacement deformation.Typical failure modes are plastic failure of internal and external steel tubes,local depression failure of concrete core columns and overall shear failure And the damage process of the concrete core column can be divided into three stages;the first stage;the damage range gradually spreads from the height of the explosion center of the core column to the back of the explosion surface,and the range continues to increase until the entire lower end of the core column;the second stage;The damage range extends from the lower end of the blasting surface to the upper side of the blasting surface.The third stage: the damage range spreads from the upper side of the blasting surface to the back,gradually connecting through the entire section to form a damage section,and shear failure occurs.(2)Analysis of the energy absorption characteristics of UHPCFDST columns under near-explosive loads shows that UHPCFDST columns have better energy dissipation capacity,of which the concrete core column dissipates the most energy in the entire structure,and the main energy dissipation mode is the core column Deformation of deformation and bending and tensile deformation of internal and external steel pipe columns.Of particular note is that the proportion of the concrete core in the total mass of the structure and the ratio of the energy absorbed by the concrete to the total energy absorbed by the structure maintain good consistency.(3)Through the comparative study of the four influencing parameters of the strength of the filled concrete,the hollowness of the section,the change in the thickness of the inner and outer steel tubes,and the form of the section: Under the same conditions,increasing the compressive strength of the filled concrete can improve the UHPCFDST column under the effect of near explosion Compared with ordinary strength concrete,the effect of filling UHPC is very significant.The hollowness of the UHPCFDST column is in the range of 24%-38%.Reducing the hollowness of the section can significantly reduce the deformation of the structure and improve the anti-explosion performance of the UHPCFDST column under near explosion.When the hollowness rate is 24%,the UHPCFDST column The deformation is minimal.Increasing the thickness of the inner and outer steel tubes of the UHPCFDST column can reduce the deformation of the UHPCFDST column under the effect of near explosion.The UHPCFDST column with round inside and outside has the least deformation and the smallest damage range under near explosion.(4)The protective effect of the foam aluminum sandwich panel on the UHPCFDST column under near explosion is more significant.Compared with the calculation results of the UHPCFDST column under the protection of the foam-free aluminum sandwich panel,under the same conditions,the UHPCFDST column The local maximum deformation and local residual deformation are significantly reduced,the damage degree and scope of the concrete core column are smaller,and large-scale continuous damage will not occur.