Semi-active Control Of Space Grid Structure With Magnetorheological Damper

Compared with the plane structure,there are some merits for space grid structures,such as reasonable stress,light weight,good seismic performance,short construction period,and strong artistic expression.In recent years,with China's major social and economic activities,the construction of a number of high standard,high standard the stadium,exhibition hall,airport terminal and other public buildings.The development of space grid structure has become an important symbol of the national building science and technology.But for the space grid structure in seismic zone,the increase of the span and the form of the complex will bring some unfavorable factors,once collapsed-Serious consequences,it is important to study on the seismic performance therefore.The traditional design method of engineering structure under earthquake,tend to produce large dynamic response,damage Or collapse,structural vibration control technology for this kind of structure safety reliable provides a new approach:This paper mainly for earthquake space grid structure of the force and deformation characteristics,the response speed,good durability,large damping force of magnetorheological damper as a shock absorber,magneto rheological damper for research and development of semi active seismic control system proposed the corresponding control theory and the corresponding simulation analysis.The main research contents include:(1)The physical characteristics of MR fluid and the working principle,working mode and dynamic model of MR damper are introduced in detail.It is obtained that the constitutive relation of Magnetorhelogical Fluids,and the damping force calculation model of magnetorheological damper.(2)Firstly,the text uses ANSYS finite element analysis software space to establishs the mode of space grid structure.Then,the mass matrix M and stiffness matrix K is exacted by the structure mode.Finally considering the effect of adding damper control,and establishing dynamics equation of space grid structure,and convert it into equations as same the state space from as.(3)By using the result of the structure seismic response under the control state,the position of the pole piece is separated from the most unfavorable response of the structure,so that the installation position of the magnetic rheological damper in the structure is reasonably selected.Then the paper puts forward the LQR control algorithm based semi-active control,using MATLAB language programming and analysis with single grid structure of magneto rheological damper under two kinds of different seismic wave time history response.Simulation results show that LQR semi-active control of structure has better control effect.(4)Analysis of the basic theory of sliding mode variable structure control system,proposed containing exponential reaching law of sliding mode control algorithm,then according to the semi-active control strategy,application of MATLAB software in simulation analysis,establishes the control and based on sliding mode control of semi active control of seismic response analysis system,to simulate space grid structure seismic response process;simulation results show that the method effectively weakened the seismic response of the structure.Then the stiffness of the structure is reduced by 20%,and the semi-active control based on the sliding mode control algorithm is analyzed.The simulation results show that the structure is not stable,and the robustness of the sliding mode control algorithm is verified.