Study On Impact And Explosion Resistance Of New Steel-Concrete-Steel Shear Wall

Steel-Concrete-Steel(SCS)composite structure is usually composed of two steel plates on the outside and a sandwich concrete layer in the middle.The structure was originally designed to resist accidental load in protective structure or immersed tube tunnel,and can withstand large explosion and impact.In this paper,a new type of SCS composite shear wall with channel steel as the connection is studied.The impact resistance and antiknock performance are investigated by the drop hammer impact test for the new type of SCS composite structure,and finite element analysis for the composite shear wall under the impact and the explosion load.The main contents and conclusions of this paper are as follows:(1)In order to study the mechanical properties of this new type of SCS composite shear wall under low-speed impact load,10 specimens of this new type of SCS composite shear wall with simple support were tested under low-speed drop hammer impact.Different impact energy,connection spacing,steel plate thickness,and hidden columns conditions were examined to study the wall’s mechanical properties.The results show that the thickness of steel plate has the most obvious influence on the impact resistance of SCS composite shear wall.When the thickness of steel plate increases from 3mm to 6mm,the maximum residual deformation of wall decreases by49.6%;in the drop weight impact test,there are three main failure modes of composite wall: mid span bending failure,local failure and separation failure of steel plate and concrete.(2)Based on the ANSYS/LS-DYNA display dynamic analysis software,a new refined finite element model of the SCS composite shear wall is established by using the whole solid element,and the dynamic response of the composite wall under the impact of the drop hammer is analyzed.The accuracy of this refined modeling method is verified by comparing with the impact test results.In addition,the influence of axial pressure and concrete strength on the dynamic response of the composite wall under low-speed impact load is discussed.The results show that the lower axial load(axial compression ratio 0.3)can reduce the deformation of composite wall by about 10%,and the impact resistance of composite wall decreases significantly with the increase of axial compression ratio;the influence of concrete strength on the impact resistance of composite wall is small,and the maximum residual deformation of C30 concrete is reduced by 8.4% compared with C60 concrete.(3)The new type of SCS composite shear wall was analyzed by finite element method under explosive load.It mainly includes two parts:(a)simulate the dynamic response of SCS composite shear wall under explosive load and study the main failure modes of the wall under different explosive loads;and(b)simulation of a simplified reinforced concrete frame core tube structure based on the multi-scale modeling method using LS-DYNA to explore the influence of different shear wall forms on the overall safety performance of the structure under explosive load.