| As a new type of combined structure,the steel plate concrete composite structure has good seismic performance and impact resistance,and is used in the CAP 1400 nuclear island structure of the domestic third-generation nuclear reactor.At present,the research of the double steel plate concrete composite structure in the field of nuclear power engineering is still immature,and there is a lack of corresponding specifications and standards,and further in-depth research is still needed.In this paper,the double steel plate concrete composite wall of the nuclear power plant is taken as the research object.The pseudo-static test and numerical model are used to study the seismic performance of the double steel plate concrete composite wall of the nuclear island structure under the in-plane action and the buckling performance of the surface steel plate.The main research results include the following aspects:(1)The in-plane pseudo-static reciprocating loading test of three double steel plate concrete composite walls was completed.The effects of different pitch-to-thickness ratios and different types of shear connectors on the in-plane failure characteristics,hysteresis curve,bearing capacity,ductility,stiffness and energy dissipation performance of the combined wall are analyzed.The results show that the double-steel-concrete composite wall has good seismic performance;the change of the pitch-to-thickness ratio has a significant effect on the buckling performance of the encased steel plate,but has a limited impact on the ultimate bearing capacity of the specimen.The setting of tie bars has a greater influence on the ultimate bearing capacity,overall stiffness,ductility,energy dissipation capacity and buckling performance of the outer steel plate.By using the inflection point method to analyze the horizontal load when the steel plate buckles under the in-plane load,it can be seen that the steel plate buckling load is less than the combined structural limit load.(2)The ABAQUS large-scale finite element simulation calculation software was used to perform finite element simulation analysis on the double steel plate concrete composite wall.By comparing the test results with the numerical simulation results,the shear ultimate bearing capacity of the double steel plate concrete composite wall and the buckling behavior of the outer steel plate were studied.The results show that the load-displacement curves of the comparison test and finite element analysis are in good agreement and can reflect the actual failure mode.By comparing the buckling load-strain curve of the steel plate obtained by the test with the buckling load-strain curve of the steel plate obtained by numerical simulation,it is found that the test results are in the same trend as the numerical simulation results,and the positions of the inflection points are similar,verifying the correctness of the finite element numerical simulation results Performance,reflecting the stress state of the combined structure steel plate buckling.The steel plate strength,steel plate thickness and connector form are key design parameters for the combined wall shear strength.The steel plate thickness,pitch-to-thickness ratio,and connector form are key design parameters for the buckling behavior of the outsourcing steel plate.(3)By sorting out the existing research results and the experimental simulation results of this paper,referring to Timoshenko's deflection surface equation of the buckling plate as the buckling mode,the critical stress correlation curve calculated by the energy method for the critical stress under the combined stress state,Applied to the outer steel plate model of the double steel plate concrete composite wall of the nuclear power plant,and uses the concept of safety factor to combine the compressive stress and the shear stress.The calculation formula of the critical buckling stress of the outer steel plate of the double steel plate concrete composite wall of the nuclear power plant is obtained and compared with the known formula. |
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