Study Of Optimization On Performance Of Bidirectional Supporting TMD Considering Damper's Deflection Angle

As an effective means of structure vibration control,Tuned-Mass-Damper(TMD)is being widely used in civil engineering.Dampers of TMD will deflect from the decoupling axis due to the separate arrangement of dampers in traditional bi-directional supporting TMD system.The deflection was ignored by previous work which may cause damping parameters of the TMD system deviate from the initial design value.This thesis investigates,the effects of the deflection angle of dampers on the performance of bi-directional supporting TMD and proposes optimization design methods for the bi-directional supporting TMD system.The major research works and achievements of this thesis are as follows:1)This thesis puts forward mechanical model of bidirectional supporting TMD considering damper deflection Angle.The governing equation of structure-TMD system is formulated using Lagrange equation method.The influence of parameters of structure-TMD system on structural responses is systematically analyzed.H? optimization design based on multi-objective genetic algorithm is proposed for the bidirectional supporting TMD considering the deflection Angle of damper.Research results show that the proposed H? optimization scheme can make the supporting TMD achieve better performance;2)The H? optimization results are studied by using a multi-degree of freedom simplified model of a real engineering structure.Under the wind attack Angle of 0 degree,the stroke of damper 2 is 5.83 times longer when the damper deflection angle is considered.Numerical simulation results indicate that damper strokes of the traditional bi-directional supporting TMD may be seriously underestimated,which brings adverse effect to performance of TMD;3)A bi-directional supporting TMD with adaptive variable damping is proposed,by which the influence of the deflection angle of the damper on the performance of the TMD is mitigated.Mechanical model of variable damping TMD is developed and the governing equation of structure-TMD system is formulated using Lagrange equation method.A two-stage variable damping TMD is designed and the TMD parameters are optimized by multi-objective genetic algorithm.The structural response of the variable damping TMD are compared with those of the ordinary TMD with constant damping level.Research result show that the adaptive TMD can achieve better performance;4)Based on an actual engineering structure,the variable damping TMD model system is designed and analyzed.The model of a multi-degree of freedom of structure as well as the TMD is presented.Comparing with the traditional decoupled case,the stretch movement of damper 1 considering damper deflection angle is increased by 4.17% and 6.67% under 45 degree of 10-year and 50-year fluctuating wind loading,respectively.It is found that when the the deflection angle of the bi-directional supporting TMD increases to a certain degree with increasing wind loading,the damper stroke will exceed the design value,resulting in the damage and failure of damper;5)A FPS-TMD is proposed,whose damping element is strictly arranged along the axis.The equation of motion of multi-stage FPS-TMD system is established.The numerical solution to the multi-stage FPS-TMD system is obtained considering stick-slip effect of FPS.A multiobjective optimization design method for the multi-stage FPS-TMD system is presented based on multi-objective genetic algorithm.Research results shows that the multi-stage FPS-TMD has less damper stroke and outperform constant friction FPS-TMD.