Theoretical Research On The Dissipation Behavior Of Shear Panel Dampers Made Of Low-Yield-Point Steel

The shear panel dampers(SPDs)made of low-yield-point steel(LYS)shows excellent hysteretic performance under cyclic load,which is of great significance in the passive energy dissipation of the structure.In this paper,a series of theoretical analysis and numerical simulation are carried out for the shear panel dampers with equal thickness and varying thickness which weak the web,so as to guide the engineering application of the dampers.The main research contents include:(1)The mechanical model of SPDs is simplified.Based on the classical plate theory and buckling theory,the unified buckling control equations of the two types of dampers are obtained under the linear elastic,small elasto-plastic deformation theory and PrandtlReuss flow theory.By solving the unified buckling control equation,the buckling critical stress of the SPD is obtained,and the correctness of the theory is proved by the analysis results of an example.The critical stress of elastic-plastic buckling obtained from the theory of small elastic-plastic deformation is used to predict the extreme load of the SPD made of LYS.The theoretical results are in good agreement with the experimental results.(2)Taking the elasto-plastic buckling critical stress as the mechanical performance index of the damper,the design method of the size parameters can be obtained: the shape factor of the shear web is recommended to be 0.9 <l <1.2;the width to thickness ratio of the shear web can be determined quantitatively according to the bearing capacity requirements of the damper;the thickness reduction factor χ of the shear web can be determined by considering the mechanical properties,failure mode,deformation capacity and economy of the damper.(3)Based on the classical plate theory and buckling theory,by introducing the influence of initial imperfections into the equilibrium path of the SPD,the unified postbuckling equilibrium equations of the damper in two configurations are obtained.By using the perturbation method,the coupled equations are transformed into a series of perturbed partial differential equations.After solving all the perturbed equations step by step,all the unknowns are obtained.Then according to the relationship between the shear strain and shear stress of the damper,the damping force model of the damper can be obtained,which improves the theoretical research of the SPD made of LYS.(4)Based on the buckling analysis results in Chapter 2,the numerical model of LYSSPD is established by using the finite element software ABAQUS.The mechanical properties of LYS-SPD with variable thickness are comprehensively discussed from the stress and strain distribution,hysteretic curve and cumulative energy dissipation.The results show that the phenomenon of high stress zone at the corner of shear web is improved after weakening the web.When the loading cycles n <15,the weakening degree has little effect on the cumulative energy dissipation of the damper,but it will affect the hysteretic performance and final energy dissipation of the damper.Combined with the theoretical analysis in Chapter 2,it can be equivalent to the reduction of the critical stress of elasto-plastic buckling of the shear web.