Research On Multiple Vertical Line Element Model Based On ABAQUS And Its Application In RC Shear Wall

Multiple Vertical Line Element Model(MVLEM)is often used in the seismic analysis of reinforced concrete(RC)shear walls.It has the characteristics of high simulation accuracy and fast calculation speed.However,at present,some excellent analysis platforms that support MVLEM,such as Open Sees,do not have pre-and post-processing modules,and have obvious deficiencies in rapid modeling and visual post-processing.The widely used general finite element analysis software ABAQUS has strong nonlinear solving ability,but it lacks the builtin macroscopic element model for RC shear wall.In this paper,based on ABAQUS,a Multiple Vertical Line Element Model(ABA-MVLEM)is developed and applied to the study of seismic behavior of RC shear walls,which provides an efficient analysis method for seismic research.The main work has been carried out as follows:(1)The theoretical models of four macroscopic elements including Fiber Beam Element Model,Multiple Vertical Line Element Model,Shear-Flexure Interaction Multiple Vertical Line Element Model,and Layered Shell Element Model are summarized,and verified by a low cyclic loading test,the results show that MVLEM has high fitting degree with experimental results and good analysis convergence,and high analysis accuracy and calculation efficiency can be obtained.(2)A Multiple Vertical Line Element Model based on ABAQUS(ABA-MVLEM)is developed.Based on the material subroutine interface UMAT,the constitutive models of concrete and reinforcement are developed for the vertical line element of ABA-MVLEM.Based on the element subroutine interface UEL,a bilinear origin oriented spring element is developed.Through the application of PYTHON script in ABAQUS,the parametric modeling program of ABA-MVLEM is built.(3)The low cyclic loading tests of three RC shear wall specimens were carried out.The seismic behavior of RC shear wall is analyzed from the aspects of hysteretic curve,skeleton curve and ductility,strength and stiffness degradation,energy dissipation capacity.The results show that the pinching phenomenon is more obvious for the specimens with small aspect ratio,and an appropriate axial compression ratio can improve the bearing capacity.(4)The ABA-MVLEM model developed in this paper is established for the low cyclic loading test specimens.The shape of the hysteresis loop obtained by the analysis is similar to that of the test hysteresis loop.The peak bearing capacity of each loading stage is in good agreement with the test value,and the main seismic performance index is close to the corresponding test value,which can meet the engineering precision requirements.The stress and strain analysis of the internal vertical element show that ABA-MVLEMhas both the characteristics of macroscopic element and the ability of meticulous response analysis.(5)The parametric analysis of RC shear wall is carried out,and the effects of aspect ratio,axial compression ratio and key parameters of edge members on RC shear wall are discussed in detail.The results show that under the same lateral displacement,with the increase of aspect ratio,the bearing capacity decreases significantly,but the stiffness degradation is slow down.Proper axial compression ratio can delay the cracking time and development speed of concrete,and show larger initial stiffnes.Edge members mainly affect the distribution of concrete and the development of cracks in the constrained area.Properly increasing the reinforcement ratio of edge members can improve the seismic performance of shear walls.