The Mechanical Properties Of Friction Damper And Its Application In Steel Frame

The development and application of energy dissipation devices are one of the most important research interests of modern buildings structure.The energy dissipated by energy dissipation device can reduce the impact of earthquakes on the main structure.Frictional damper,a kind of energy dissipation device,can protect the main structure by dissipating seismic energy by the relative movement of friction plates with a certain frictional resistance,and has the advantages of stable energy consumption.Friction damper is divided into translation and rotation type.Compared with the translational type,unlimited of the movement scale,the rotational type frictional damper is more conducive to exert the energy dissipation capacity of the energy dissipation device under the action of rare earthquake.At present,there are a lots of relative research results and application examples of the translational friction damper,an the application technology is also mature.The rotational friction damper is a new type of damper,in order to achieve its engineering promotion and application,an in-depth study,the mechanical performances of friction damper,the connecting method between the structure and friction damper,is needed.In this study,the finite element analysis software ABAQUS was used to quantitatively analyze the mechanical properties of the rotational friction damper.A simple and feasible design method of the friction damper and a new type of rotational friction damper connected method was proposed,the design method of the proposed rotational friction damper is used to design a new type of rotational friction damper,and then a representative multi-story and high-rise steel frame model with friction damper is established in the OpenSEES seismic analysis software.The dynamic elasto-plastic time-history analysis under frequent seismic actions and under infrequent seismic actions,including the following contents:The finite element analysis model of rotational friction damper was established by finite element analysis software ABAQUS.The formula of bearing capacity of rotational friction damper was obtained by the method of parameter regression analysis.The main parameters include the friction coefficient of friction surface,friction surface number and bolt pre-load.A simple and feasible design method of rotating friction damper is proposed in combination with the existing code for seismic design.That is,the maximum story drift angle of the structure is determined by the pushover analysis of the structure,and the target story drift angle is determined according to the seismic design code,then getting the target displacement reduction rate,and then determine the elastic stiffness ratio of the damper,then the elastic stiffness and yield strength capacity of the damper in each floor can be decided,the damper can be designed,Through the structure overall relative tolerance to test design quality of the damper.It's a way to reduce earthquake damage to main structure by setting damper in building structure and consuming seismic energy.The vibration damping principle of the friction damper is to consume the seismic energy through the mutual error between friction plates with certain friction resistance to protect the main structure of the friction damper.The friction damper is a kind of friction dampers.Besides the characteristics of the energy dissipation of friction dampers,the friction energy dissipation capacity of the friction dampers is greater than that of the similar translation dampers.In this paper,the performance of the friction damper is systematically analyzed by using the finite element analysis software ABAQUS,and the representative high-rise steel frame models including friction dampers are included in the OpenSEES seismic analysis software.The properties of the whole steel frame with friction dampers are analyzed qualitatively,and the main contents are as follows:The main parameters affecting the bending bearing capacity of the rotating friction damper include the rotational friction coefficient of the friction surface,the number of the friction surface and the pre tightening force of the bolt.The finite element model of the rotary friction damper is established by using the finite element analysis software ABAQUS,and the evaluation formula of the rotational friction damper's bearing capacity is obtained through parametric regression analysis.Combined with the existing seismic design code,a simple and feasible method is put forward,the rotating friction damper for seismic design is determined by the modal analysis of the structure of weak structure layer displacement angle and target angle of floor displacement,determining target displacement reduction rates,and to determine the elastic damper stiffness ratio calculation,each layer of elastic damper stiffness,determine the yield capacity of each layer of the damper,according to the yield capacity to determine the specific size of the damper,the overall structure of relative tolerance test determines the damper section size.A new type of connected method between the rotating friction damper and the main frame is proposed.Using the proposed design method for damper,the damper design is carried out on the 4,10 and 20-story steel frames,and a dynamic time history analysis about the steel structure using a new type of rotational friction damper is done.In the time history analysis,the seismic excitation on the common steel frame model and the steel frame model with a new type of rotating friction damper are considered under the action of frequent earthquake and rare earthquake of the three earthquake waves.The influences of the damper on the internal drift angle,energy dissipation and other conditions which improving the seismic performance of the structure is studied.The results show that the bending moment vs.rotation hysteresis curve of the rotating friction damper is full,which shows that it has good energy dissipation capacity.The seismic decreasing ratio of the steel frame structure with friction damper is about 25%under frequent earthquake,and is about 30%under rare earthquakes,and the seismic performance of steel frame structure is obviously improved.