| When the earthquake comes,the location of the weak layer of a structure will be destroyed first,which will lead to the destruction of the adjacent layer,and seriously lead to the destruction of other floors,and become the main factor leading to the collapse of the whole structure.Under various building functional requirements,there are many vertical irregular structural systems with weak stories.The traditional "hard resistant" seismic design method is difficult to ensure the performance requirements of the vertical irregular system with weak stories under different levels of ground motion.The structural vibration control technology can reduce the damage of the structure caused by the earthquake by using the control device,improve the ability of the engineering structure to resist the disastrous earthquake action,make it possible that the engineering structure will lose less or not be damaged under the disaster action and fully meet the performance design requirements.More and more researchers will focus on the structural vibration control.With the continuous improvement of structural vibration control technology,the structure vibration control system of passive control,active control,semi-active control and intelligent control has been formed.Damper is a kind of passive and semi-active seismic control device.It is an effective way to reduce the influence of seismic action on the structure itself by adding damper to the vertical irregular structure system with weak story.The IMD with larger inertia mass in the new type of inertia mass damper can effectively reduce the dynamic response of the structure to earthquake by using its inertia mass effect.The main purpose is to transform the axial displacement into the rotating motion of the flywheel through its internal roller lead screw,so as to enlarge its additional mass,so that it can provide greater damping force and inertia force to resist the earthquake response.Compared with the traditional damper,timd has the advantages of low energy consumption,high efficiency,convenient maintenance in the later period,long use time,and relatively small pollution to the environment,so in this paper,timd is applied to study the seismic control performance of the vertical irregular structure system with weak layers.The main research work is as follows:(1)Two new types of inertia mass dampers,tuned viscous mass damper and electromagnetic inertia mass damper,are introduced.Based on the passive and semi-active control principles,design parameters and mechanical performance test indexes of the two kinds of dampers,the general mechanical models are established respectively.(2)According to the current aseismic design code and combined with the damage characteristics of the vertical irregular structure with the weak layer,three kinds of typical irregular structure models with the weak layer are established,which are the regular structure,the one-way eccentric structure with the plane and vertical irregular structure,and the two-way eccentric structure with the plane irregular and vertical regular structure,The dynamic model of the system of inertia mass damper and vertical irregular structure is established,and then the equation of motion of the structure is transformed into the standard equation of state by using the theory of state space correlation.(3)The dynamic time history analysis method is used to simulate the structure.A damper is placed on each floor of the structure,and the peak response of the structure under the passive control of two kinds of dampers is obtained.The seismic control effect of the weak floor of the structure under the three models is compared and analyzed.Among them,the interlayer displacement damping ratio of model 1 is 66.4%,the interlayer displacement damping ratio of model 2 is 29.4%,the corner damping ratio is 33.1%,the interlayer displacement damping ratio of model 3 is 26.5%,and the corner damping ratio is 30.5%.The results show that the inertia mass damper can control the vibration response of the weak layer and the whole structure well,while the passive control effect of the eccentric structure is not as good as that of the regular structure because of its torsional coupling effect.Then two dampers are placed in the weak layer and adjacent layer,and the control effect of one damper and two dampers in the weak layer is compared.The results show that the interlayer displacement damping ratio of model 1 is 67.3%,that of model 2 is 51.9%,that of model 2 is 43.1%,that of model 3 is 49.3%,and that of model 3 is 38.5%.The results show that the number and location optimization of dampers can improve the seismic control performance of the vertical irregular structure with weak story.(4)Through the modal analysis of the structure by using the mode decomposition method,the absolute displacement of the structure under each first mode is obtained,the proportion of each mode is analyzed,and the natural frequency and damping ratio of the structure are obtained.The results show that the first mode accounts for 91.0%,the first mode accounts for 84.1%,while the first three modes account for 94.6%,the first mode accounts for 81.1%,and the first three modes account for 92.4%.The results show that the proportion of the first mode of the eccentric structure will be reduced due to its torsional effect,and the selection of the number of modes should be paid attention to in the design of the modal space control method.(5)Through the semi-active control analysis of the structure by the sliding mode control algorithm,the results show that after the semi-active control of the structure by the sliding mode control algorithm,the damping ratio of the layer displacement of the first weak layer of the model reaches 70.4%;the damping ratio of the layer displacement of the second weak layer of the model reaches 58.2%,and the damping ratio of the corner reaches 61.5%,The displacement damping ratio of the three weak layers is 57.3%,and the angle damping ratio is 53.3%,which shows the feasibility and effectiveness of the semi-active control strategy based on the sliding mode algorithm. |
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