Parameters Optimization And Different Forms Of Several Dynamic Vibration Absorbers

Mechanical vibration generally exists in engineering practice.Dynamic vibration absorber was created to reduce the influence of harmful vibration.Dynamic vibration absorber is an additional system used to connect to the excited main system to reduce the its vibration.The traditional dynamic vibration absorber has poor control effect on low frequency vibration.In order to improve the performance of dynamic vibration absorber,in this paper,the traditional dynamic vibration absorber is improved.The main research contents are as follows:(1)A new type of DVA is proposed by introducing amplification mechanism and negative stiffness device into Voigt type dynamic vibration absorber.Utilizing H∞optimization criterion,the optimal parameters are counted and the performance of DVA is studied in vibration reduction.The correctness of the analytical solution is verified by comparing the analytical solution with the numerical solution.Compared with other DVAs under harmonic and random excitations,it is verified that DVA in this paper could reduce the resonance amplitude of system greatly,which provides a theoretical basis to designing new type of dynamic vibration absorber.(2)Lever mechanism was introduced into grounded DVA.The optimal parameters of the DVA are designed.It is found that there are three cases,positive stiffness,negative stiffness and zero stiffness when analyzing the optimal stiffness ratio,and the vibration reduction effect of the three cases is analyzed respectively.Compared with other DVA models,the results show that the vibration reduction effect of DVA is the best when the ground stiffness is positive.(3)A grounded viscoelastic DVA is proposed.By analyzing the amplitude frequency curve of it,it is found that there are three fixed points in this system.Based on the fixed-point theory,the optimal frequency ratio,the optimal damping ratio and the optimal stiffness ratio of the dynamic vibration absorber are determined.The accuracy of the analytical solution is verified by comparing with the numerical solution.The comparison with other DVA models shows that this kind of DVA have good performance in vibration reduction.(4)The model of semi-active dynamic vibration absorber is studied,the control strategy is proposed.The analytical solution is calculated by using the average method.And its accuracy is verified conparing with the numerical solution.The optimal parameters of the model are selected.Compared with the N-Vogit DVA,the results show that the model in this chapter has better damping performance under medium frequency excitation.The research content of this paper is summarized at last,and the possible future research direction is discussed,which provides ideas and suggestions for the follow-up research.