| The possibility of structures being impacted by explosion is increasing because of the frequent explosion in recent years,and the security of people’s life and property is becoming more and more threatened.Researchers at home and abroad need to find more safe protective structures and to carry on the anti-explosion reinforcement design to the existing projects urgently.One of the most important links is to study the dynamic response of structures or members composed of constructions under explosive impact load.FRP-concrete-steel double-skin tubular column,a new type of composite member,has been proposed and studied in recent years,which not only inherits the advantages of duplex hollow concrete filled steel tube column,such as good earthquake resistance,high bearing capacity,good plasticity and ductility.Moreover,it solves the problems of corrosion and poor fire resistance of the outer steel tube of duplex hollow concrete filled steel tube columns.The carbon fiber reinforced polymer is widely used because of its higher elastic modulus in fiber reinforced polymer.Due to its good mechanical and economic performance,it has been more and more used in practical engineering construction.In order to study the ability of CFRP-concrete-steel double-skin tubular columns to resist explosive impact load,this paper mainly uses the finite element numerical simulation method to study the anti-explosion dynamic response and parametric analysis of design factors of CFRP-concrete-steel double-skin tubular columns.The main contents of the study are as follows:1.A large number of literature and related research results were consulted to understand the basic theory of explosion shock wave,such as the basic phenomena of explosion,the propagation law of blast wave in the air,the connotation and calculation method of blast wave parameters and the law of similarity of explosion.The dynamic characteristics of the materials and the research status of the dynamic response of structures or members under explosive loads by scholars at home and abroad were also summarized;2.In order to verify the accuracy of the parameters related to blast wave in the same medium before numerical simulation of the interaction between blast wave and structure or component,the detonation evolution process of TNT explosive in free air was numerically simulated.The propagation law of blast wave in free air and the effect of mesh size on the peak value of pressure were analyzed,and the simulation values of relevant parameters of blast wave were compared with the predicted values of several commonly used empiricalformulas.The results show that the values obtained by numerical simulation were in good agreement with the predicted values obtained by empirical formula,which provides the relevant basis for the accuracy of the subsequent simulation.3.Based on the large-scale explicit dynamic analysis software ANSYS/LS-DYNA,the integral coupling finite element model of TNT explosive—air—CFRP-concrete-steel double-skin tubular column was established.The coupling between blast wave and column was realized by ALE multi-material fluid-Solid coupling algorithm.The anti-explosion response characteristics of columns,such as failure morphology,displacement,surface strain distribution of CFRP,equivalent stress and first principal stress of concrete,steel tube and CFRP were analyzed emphatically.4.According to the conclusions obtained above,the numerical analysis models of CFRP-concrete-steel double-skin tubular columns under different design parameters such as concrete strength grade,scale distance,section steel ratio,CFRP thickness,hollowness ratio,axial load level and section type were established.The time-history curve of displacement of column was selected as a comparison to analyze qualitatively the influence of each design parameter change on its anti-explosion performance.The research contents and results can provide reference for the anti-explosion design of this kind of components. |
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