Impact And Blast Resistance Of Steel-Concrete-Steel Sandwich Panel With Energy Absorbing Layer

With the rapid increase in the number of impact and explosion events in recent years,the safety protection of buildings has increasingly become a research focus in the engineering community.The steel-concrete-steel sandwich structure(SCS sandwich structure)has the characteristics of high load bearing capacity and high ductility,and is particularly suitable for resisting accidental loads such as impact and explosion.Polyurethane foam(PUF)materials have been widely used in energy absorbing systems in transportation engineering,aerospace engineering and other fields due to their excellent cushioning energy absorption properties.The application of PUF foam material in SCS sandwich panel as an energy absorbing layer to form PUF-SCS composite panel,which can fully combine the advantages of the two and has a high practical engineering significance and scientific research value for improving the impact and explosion resistance of the structure.In this paper,the dynamic response and failure mechanism of the PUF-SCS composite panel under impact and explosion are analyzed,and the influence of different parameters on the impact and explosion resistance of composite panel is systematically investigated through finite element simulation analysis.The main research contents are as follows:(1)The PUF-SCS composite panel was designed,mainly considering the selection of connector,the determination of the number of connectors,the determination of the connection mode between the PUF foam energy absorbing layer and the SCS structure,etc.In order to obtain the mechanical properties of each component material of PUFSCS composite panel,the material test of steel,concrete and polyurethane foam was conducted.Based on the finite element platform LS-DYNA,the finite element model of PUF-SCS composite panel under the impact of cylindrical impactor and hemispherical impactor was established respectively.The comparison between the numerical simulation results and the impact test results of similar panel structures shows that the numerical simulation method can simulate the whole process of structural response under impact.(2)The dynamic response analysis and failure mode classification of the composite panels under impact of different impactor were carried out.Under the impact of cylindrical impactor,the failure mode of PUF-SCS composite panel was global bending failure,and its dynamic response process could be divided into three stages: PUF compression stage,SCS structure bearing stage and rebound stage.Under the impact of hemispherical impactor,the failure modes of PUF-SCS composite panel are local failure and global bending failure,and the dynamic response process can be divided into four stages: PUF compression stage,SCS structure local deformation stage,SCS structure bending deformation stage and rebound stage.The influence of parameters such as the presence or absence of polyurethane foam energy absorbing layer,concrete thickness,polyurethane foam layer thickness and steel plate thickness on the impact force,displacement and energy absorption capacity of each component of PUF-SCS composite panel was analyzed.(3)The finite element model of PUF-SCS composite panel under the close-range explosion and the far-range explosion was established,and the rationality of the numerical simulation method was verified from the empirical formula and the explosion test results of specimens provided in the literature.The explosion numerical results show that the failure mode of PUF-SCS composite panel is the coupling failure of bending and shear under the close-range explosion.In the case of the far-range explosion,the overall bending failure was the dominant failure mode of the PUF-SCS composite panel.Finally,from different perspectives such as displacement,response time and energy absorption capacity of each component,the influence of factors such as explosive weight,standoff distance,the presence or absence of PUF layer and its thickness,concrete thickness and steel plate thickness on the blast resistance of PUFSCS composite panel was systematically investigated.