Numerical Simulation Of Seismic Performance Of Self-Centering Beam-Column Joints Reinforced With Superelastic SMA Bars And ECC Materials

Compared with the traditional seismic structure,the self-centering structure can eliminate the residual deformation caused by the yield energy dissipation.By setting the self-centering component or device in the structure,the residual deformation of the structure after the earthquake can be eliminated,and its function can quickly automatic restore after earthquakes.It provides guarantee for the continued use and rapid reconstruction of post-disaster structures.At present,the self-centering structure has become one of the research hotspots in the field of seismic engineering.In recent years,more and more scholars have paid attention to the research and development of a new type of energy-intensive seismic structure system with self-centering function by using intelligent materials and high-performance engineered cementitious composite.Shape Memory Alloy(SMA),a new smart material,has excellent characteristics like sensing,driving,high damping,corrosion resistance and fatigue resistance.SMA material has the ability of self-centering and energy dissipation,which makes it an ideal material for self-centering structure.Engineered Cementitious Composite(ECC)has the characteristics of strain hardening and multiple fine cracks cracking,which can improve the ductility,durability,crack resistance and permeability of the structure.In this paper,numerical simulation of self-centering SMA/ECC frame beam-column joint is carried out on the basis of previous experimental research.A new numerical analysis model for the joint is established.The seismic performance of several points of selfcentering under the low-period reciprocating load is numerically simulated.Considering many parameters,the factors affecting its self-centering ability and seismic performance were analyzed.This paper mainly conducts the following studies:(1)Self-centering SMA/ECC frame joints test and result analysis.The size and reinforcement of the joints test model are described in detail.The experimental data and basic parameters of SMA,ECC and other material are given.Introduced the loading setup and loading step in the experiment.The test results of the joints are analyzed.The research shows that: Frame beam-column joints reinforced with superelastic SMA bars and ECC materials can improves the self-centering ability and seismic performance of the joints.(2)Establishment of numerical simulation model of self-centering SMA/ECC frame joints.According to the results of material test and joints test,the basic parameters of SMA,ECC and RC material numerical simulation model are determined,and the parameters of each element in the beam column joint are determined.Based on seismic engineering finite element software Open Sees,the joints shear plate calculate program of the joints core region was developed,and the SMA-ECC separation model was used.Established the numerical simulation model of self-centering SMA/ECC frame joints.(3)Numerical simulation and data analysis of self-centering SMA/ECC frame joints.Using the established finite element analysis model,the nonlinear analysis of the self-centering SMA/ECC frame joints was carried out.By comparing the numerical simulation results with the experimental data,verify the correctness and applicability of the established numerical simulation model.Research shows that: The numerical simulation model established in this paper is consistent with the experimental data.The model can better simulate the seismic performance of self-centering SMA/ECC frame joints.(4)Numerical simulation parameter optimization analysis of self-centering SMA/ECC frame joints.In order to optimize the design of frame joints,based on the established numerical simulation model,the parameters of SMA/ECC frame joints are optimized.The design parameters including the configuration quantity,replacement length and yield strength of SMA,and the use area,the ultimate tensile strain and the tensile strength of PVAECC material.The influence of these parameters on the self-centering ability and seismic performance of the joints are analyzed.Research shows that: Changing the configuration of SMA materials will significantly affect the bearing ability and selfcentering ability of the joints.The ECC material has more influence on the energy dissipation ability of the joints.The superelastic SMA/ECC frame joints is a structural component which have high energy consumption and self-centering function.The new self-centering energy dissipation joints can effectively improve the seismic performance of the frame structure,and reduce the residual deformation of structure after the earthquake.It can reduce the damage of the structures caused by the earthquake,and quickly restore the function of structures after earthquakes.It has good comprehensive social benefits and broad prospects of engineering application.