Design And Parameters Optimization Of Three-element Type Dynamic Vibration Absorbers

Vibration control is becoming important in many engineering practices.One of the common devices for vibration control is dynamic vibration absorber,which is widely used due to its properties such as efficiency,reliability,and low cost.A large number of viscoelastic materials were used in vibration control engineering and its mechanical model is more suitable for the Maxwell model.The Maxwell model is introduced into the dynamic vibration absorber,so that the optimal parameters of dynamic vibration absorber with the Maxwell model is studied in this thesis.At the same time,two kinds of negative stiffness dynamic vibration absorbers are introduced to improve the control performance of the DVA in low frequency domain.The work in this thesis is as follow:(1)Considering the Kelvin and Maxwell model as the research objects,the system responses for the two models are studied based on forced vibration of single degree-of-freedom system.The amplitude-frequency response curve and phase-frequency response curve are drawn out respectively.By comparing the amplitude-frequency response curves of the two models,it could be concluded that the control performance of Maxwell model is much better than that of the Kelvin model in the case of small damping,which is useful to the design and revision of vibration system.(2)Considering a new type of the grounded three-element type dynamic vibration absorber as the research object,the optimal analytical solution is studied based on H∞ optimization principle.According to the fixed point theory and H∞optimization principle,the design formulas of the optimal parameters are obtained.(3)A new type of the grounded three-element type dynamic vibration absorber with negative stiffness is studied in detail.According to the characteristics of negative stiffness element,the optimum negative stiffness ratio is also established and it could still keep the system stable.The comparisonswith three other traditional DVAs under the harmonic and random excitations show that the presented DVA performs better performance in vibration absorption.This result could provide theoretical basis for optimum parameters design of similar DVAs.(4)A new kind of three-element type dynamic vibration absorber with negative-stiffness spring is studied in detail.The presented DVA in this paper performs better in vibration absorption.The damping effect is far better than three existing dynamic vibration absorbers.