Mid-story Isolation And Intelligent Fuzzy Control Study On Large-chassis Structure

In recent years, the large chassis structure has become one of the most commonlyused structures in the large-scale commercial and residential construction projects. Butthe vertical stiffness of this structure varies greatly, in order to enhance the seismicperformance, it’s necessary to adopt some special structure treatment. The isolationlayer，which is set between the superstructure and chassis，would be a very effectiveway to solve this problem. However, when experiencing severe earthquakes，Thisisolation method can easily lead to great relative displacement on the isolation layer，which would further cause the tensile failure of the isolation bearing，and increase thepossibility of overturning of the superstructure. In order to solve such problems, thispaper carried out the following works:(1) Detailed description of the basic principles and mechanical properties of somefrequently-used isolation bearing and the MR dampers has been given. Meanwhilethis paper also analyzed the mechanical calculation model for MR dampers，anddiscussed the performance and usable range of these types of dampers, and finallypresented the isolation measures and the implementation of the large-chassis structure.(2) The finite element analysis software SAP2000has been used to establish adynamic analysis model for a large-chassis isolation structure compared with thecomputational model of the non-isolated structure. Through the corresponding seismicresponse analysis, the paper discussed several problems which the great relativedisplacement on the isolation layer would further cause the tensile failure of theisolation bearing，and increase the possibility of overturning of the superstructure whenencountering severe earthquake. In the end，the ideas and technical measures to control the relative displacement of the isolation layer were presented.(3) After studied the simplified calculation model of the large-chassis isolatedstructure and analyzed the corresponding seismic response. meanwhile，compared withthe dynamic analysis, the results were analyzed by SAP2000and SIMULINK，the paperprobed into the main rules and differences of these3kinds of analysis，and presentedsome conclusions and recommendations for reference.(4) Based on the simplified calculation model above，using the SIMULINKtoolbox，the paper presented the hybrid control method combining large chassisstructure isolation with the MR damper to control the relative displacement of theisolation layer， and established the corresponding mechanical analysis andcomputational model with using the fuzzy control algorithm. The paper also establishedthe rule base controlled by the relative displacement and velocity of isolation layer andthe output from the MR damper. on this basis，the paper further analyzed the seismicresponse of the large chassis structure when hybrid controlled. In addition，comparedwith the analysis of the large chassis structure without MR damper，the correspondingcontrol mechanism and laws were explored.The research shown that，the calculation results of the simplified calculation modelwere established in the paper. the SIMULINK computational model and the finiteelement model were analyzed by SAP2000in harmony，so that the method wasconvenient to apply for its simple calculation. Setting the MR damper on the isolationlayer would be an effective way to control the relative displacement of the isolationlayer and consume the energy of an earthquake. Besides，through the input ofEL-CENTRO seismic waves, artificial seismic waves and Taft earthquake waves，theseismic response comparison analysis showed that the greater relative displacement ofisolation layer was，the more effective hybrid control would be, the effect relationshipbetween the relative velocity and the hybrid control as above. all these results indicatedthat the hybrid control method can both effectively play the isolation performance ofseismic isolation bearings and prevent a series of problems brought about by too muchrelative displacement of the isolation layer. Taking all the above factors intoconsideration，we may safely come to that the reliability of hybrid control for suchkinds of structures has been greatly improved，and a new approach for the seismic design of the chassis structure has been provided.