Research On Seismic Response Analysis Method For Structures With Metal Dampers Based On Inter-history Iteration

After decades of development,energy dissipation damping technology has been greatly developed,with more diversified types and more mature theory.It has become an effective means of structural se ismic response and damage control.Among them,metal dampers,with the advantages of low cost,convenience of construction and ease of replacement,have been widely used in major seismic areas all over the world.Elastic dynamic analysis theories and calculation programs of structural system are extremely mature.However,metal dampers with a certain degree of nonlinear behavior,which makes the whole structure form a typical local nonlinear system,increase the difficulties of seismic response analysis.At present,there are two types of methods for dynamic response analysis of structures with metal dampers under frequent earthquakes.One is the time history analysis of nonlinear equations of motion by numerical integration method,which is inefficient and occasionally unstable due to nonlinearity;the other is the equivalent linearization method,whose equivalent parameters are frequently decided by predicted maximum structural response,without considering the influence of time history of structural response on equivalent parameters.In this paper,based on the existing research,a n inter-history iteration method for seismic response analysis of structures with metal dampers is proposed,and the accuracy and stability of the method are anal yzed by theoretical analysis and numerical simulations.The research and conclusions are listed as follows:(1)According to the local nonlinear characteristics of structures with metal dampers,the Sherman-Morrison theorem is introduced to reduce the dimension of the inverse matrix in Rosenbrock integration method,resulting an efficient elaborated simulation method for seismic response analysis.The results of the proposed method coincide with those of the original method,but computational efficiency is improved obviously.(2)Based on the theory of linearization and the law of seismic response of structures with dampers,the calculation formulas of the equivalent linearization parameters are theoretically derived.Then,based on existing research,two methods for calculating equivalent stiffness based on average tangent stiffness and weighted average tangent stiffness are proposed respectively.Accuracies of different equivalent calculation formulas are compared and analyzed by numerical simulations.The results indicate that response deviations of the formulas by theoretical derivation is relatively lower.(3)Based on the strategy of inter-history iteration,a seismic response analysis method of structures with metal dampers is proposed.The favorable convergence and reliability of the proposed method are verified by numerical simulations of inter-storey shear model and plane frame model.