| Installing dampers in the structure is an effective method to decrease dynamic respond under seismic effect. By consuming partial seismic energy with dampers, seismic response of the main structure is reduced and the safety is ensured. Structural vibration control is widely used for its advantages of simple structure and no demand of external energy. Shape Memory alloys(SMA) are more and more applied in structural vibration control with their characteristics of shape memory effect and superelastic effect. Nowadays, researchers have designed several dampers by applying SMA. According to the self-centring the SMA damper which is designed before, damper and related passive control structure were analyzed based on material constitutive model and mathematical model. Meanwhile, the influence of installation position at different floor on structural control was analyzed. Works of this paper are as follows:(1) Numerical simulation on mechanical property of the SMA damper was conducted based on material constitutive model to study the influence of the variation of some material parameters of damper on the energy dissipation capacity. As the damper is displacement-based, based on the SMA damper designed before, the strain of SMA could be obtained by input of displacement excitation according to equilibrium equation of force and displacement. The stress of energy dissipating group could be obtained by equation of Brinson constitutive model and material constitutive model. Considering the influence of the length and diameter of SMA wires、pre-strain and pre-stress on spring, the dampers with different parameters were designed. And numerical simulations of mechanical property were conducted with the program. And analyze the influence of variation of the parameters to single cycle energy dissipation、equivalent tangent stiffness and equivalent damping ratio.(2) Mathematical model was introduced to the damper. The relationship of load and displacement of nonlinear hysteretic systems could be described in Bouc-Wen model. The shape of hysteresis curve was controlled by the differential equation which is formulated by several parameters. In order to study the relationship between parameters of mathematical model and parameters of dampers, the influence of parameters in Bouc-Wen model to hysteresis curve was analyzed. Based on parameters of dampers, parameters of mathematical were obtained. With this way, parameters of mathematical could be calculated based on the known parameters of dampers. Apply Simulink to obtain the relationship between load and displacement and compare the results. This indicates accuracy of simulation analysis.(3) Calculating model was determined by story shear model based on passive control structure and basic parameters of structure were obtained. According to Brinson constitutive model and mathematical model, two programs simulating vibration response of passive control structure were written, respectively. Time history analysis of a 4 story steel frame with the damper was conducted with two analysis ways. By comparing maximal story drifts、peak values of acceleration、maximal story drift angles and maximal story shear force between two ways and another one without control, the result shows great damping effect of the SMA damper to structure and the validity of two simulating ways.(4) In order to analyze the influence of installation position at different floor to the control effect of vibration response, the objective function and the weight parameters were determined with the principle of damping control. Based on Bouc-Wen model, simulation of vibration response of passive control with different installation position was conducted, and in order to obtain the favorable arrangement it was put into the objective function. According to a 5 floor steel structure, the simulations of vibration respond with single damper or couple dampers both installing at different floor were conducted to analyze the damping effect. By putting into the objective function, the favorable arrangement was analyzed. |
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