Analysis Of Dynamic Characteristics Of Nonlinear Damping Dynamic Vibration Absorber

Traditional linear dynamic vibration absorbers have been widely used in practical production and life due to its simple structure and high reliability.Traditional linear dynamic vibration absorbers have been widely used in practical production and life due to their simple structure and high reliability.However,adding a certain amount of linear damping can broaden the frequency domain of vibration control,but it worsens the vibration absorption effect near the anti resonance point.Moreover,under certain conditions,linear dynamic vibration absorbers have limitations on amplitude suppression effects.Nonlinear dynamic vibration absorbers can improve the dynamic characteristics of linear dynamic vibration absorbers and further enhance their amplitude suppression effect.This thesis proposes a nonlinear damping device based on cam mechanisms,which can accurately achieve various forms of damping by designing cam profiles.The device was introduced into the dynamic vibration absorber,and a nonlinear damped dynamic vibration absorber model was established,and the dynamic characteristics of the model were analyzed.The main research contents of this thesis are as follows:(1)Based on the moving cam mechanism,three nonlinear damping devices are designed.The equivalent damping coefficient of the nonlinear damping device is calculated through force analysis.The traditional Voigt type dynamic vibration absorber model and the large stiffness damping grounding type dynamic vibration absorber model are introduced.The linear damping in the model was replaced by a nonlinear damping device with a cam mechanism,and four dynamic vibration absorber models were finally designed.(2)The mechanical analysis of the Voigt type dynamic vibration absorber model with segmented linear damping,circular arc contour cam damping,and the segmented linear damping grounded type dynamic vibration absorber model is performed,and the transient equivalent damping is obtained.Using the principle of equal damping energy dissipation,the steady-state equivalent linear damping and analytical solution of the model are obtained.The mechanical analysis of a displacement square terms damping grounded dynamic vibration absorber model was carried out,and the transient equivalent damping was obtained.The analytical solution of the model was obtained by using the harmonic balance method.The amplitude frequency response of the main system is obtained through analytical solution and verified by numerical solution.(3)Steady state characteristic analysis was conducted on each model.The Voigt type dynamic vibration absorber with piecewise linear damping can make the amplitude of the main system 0 at the anti resonance frequency,and has a good suppression effect on the amplitude of the main system near the natural frequency;The Voigt type dynamic vibration absorber with segmented linear damping can better suppress the amplitude of the main system at a specific frequency when it is at the same height as the peak value of the linear system;The grounded dynamic vibration absorber with piecewise linear damping can achieve a 0 amplitude of the main system at the anti resonance frequency by setting a damping cut-off point.Compared with the linear damped grounded dynamic vibration absorber model,it can effectively reduce the amplitude of the main system;The grounded dynamic vibration absorber with displacement square terms damping can effectively reduce the amplitude of the main system,and also has an amplitude suppression effect on the main system within a certain range that is greater than the low-frequency peak frequency.