| The double steel plate concrete composite structure(SC structure)is a steel-concrete composite structure formed by the combination of steel plate and concrete,and the steel plates on both sides of the outside are connected by tension connectors.Under the stress state,the advantages of the material can be fully utilized,showing the characteristics of high bearing capacity,high stiffness,good sealing,convenient construction,and good anti-explosion impact performance.As a part of the SC structure,the tension connector has an important contribution to the bearing capacity and energy dissipation capacity of the structure.However,when subjected to impact load or large deformation,the first failure of the connector limits the deformation capacity and energy dissipation capacity of the double steel plate concrete composite structure,thus limiting the advantages of the impact resistance of the structure.In order to remove this limitation and give full play to the good impact resistance of SC structure,this paper proposes to use Kinked Rebar(KR)as a connector of double steel plate concrete composite structure,and name it as Kinked Rebar connector-double steel plate concrete composite structure,referred to as KR-SC slab.Through the good deformation characteristics of KR connectors,the deformation capacity and energy dissipation capacity of double steel plate concrete composite structure are improved,so as to achieve the purpose of improving the impact resistance of the structure.In this paper,KR-SC slab is taken as the research object.The impact resistance of KR-SC slab is studied from four aspects: KR-SC slab unit tensile test,pendulum impact test,static concentrated loading test and finite element analysis of impact resistance of KR-SC slab under impact load.The main research contents and conclusions of this paper are as follows:(1)In order to study the mechanical properties of KR connectors,tensile tests were carried out on 12 KR-SC slab unit specimens.The effects of connector diameter and wave angle on failure displacement,tensile force and energy dissipation capacity of KR-SC slab element specimens were studied.The test results show that the failure modes of the connectors in the KR-SC slab element specimens can be divided into two types: fracture after straightening and fracture without straightening.With the increase of the connector diameter and the wave angle,the failure displacement,tensile force and energy dissipation capacity of the KR-SC slab element specimens also increase,but the wave angle has little effect on the tensile force.The calculation method of KR connector strength is proposed,which is in good agreement with the test results.When the kinked angle of the connector is 45°,the energy dissipation capacity of the KR-SC slab unit specimen is the best.(2)In order to study the impact resistance of KR-SC slab,the pendulum impact test was carried out on six KR-SC slab specimens.The kinked angle of KR connectors,the diameter of KR connectors,the arrangement spacing of KR connectors and the presence or absence of studs were set as different parameter variables to study their impact resistance of KR-SC slab.The test results show that the impact process of KR-SC slab can be divided into four stages: inertial force response,stress propagation,membrane force development and unloading springback.After the test,the KR-SC slab specimens have different degrees of overall bending deformation and local depression;the influence of the spacing and diameter of KR connectors on the impact resistance of the composite plate is more prominent,especially in terms of deformation.(3)The finite element model of KR-SC slab specimen was established,and the ratio of model size to KR-SC slab specimen was 1:1.The impact resistance of KR-SC slab was analyzed by ABAQUS/Explicit explicit analyzer.By comparing with the experimental results,the accuracy of the modeling method in this paper is verified.The influence of six parameters,such as impact energy,steel bar diameter,arrangement spacing,kinked angle,wave length and concrete strength,on the impact resistance of KR-SC slab is further discussed.The results show that the energy dissipation capacity is the best when the starting angle of KR connector is set to 45°,the energy dissipation capacity is the best.Based on the KR-SC slab with a wave angle of 45 °,the analysis of six parameters such as different impact energy,steel bar diameter,arrangement spacing,wave angle,wave length and concrete strength is carried out.The impact energy has a significant effect on the impact resistance of KR-SC slab.Under the impact energy of 20 k J,the diameter,arrangement spacing,kinked angle and concrete strength have a great influence on the impact resistance,among which the arrangement spacing has a significant effect,while the length of the connector has no obvious effect.The energy consumption of KR-SC slab is more than 80%,which shows that the impact resistance of KR-SC slab is better. |
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