Inertial Nonlinear Energy Sink And Its Suppression Of Structural Vibration

The nonlinear energy sink can dissipate the vibration energy of the structure in unidirectional and irreversible manner in a wide frequency range,and has a broad application prospect as a passive vibration absorber.The nonlinear energy sink is mainly composed of a nonlinear elastic element,a linear damping element and an inertial element.The mass of the damping and elastic elements is usually ignored.Therefore,the mass of the inertial element is the mass of the nonlinear energy sink.Currently,the mass is the inertial element usually used in nonlinear energy sinks.In order to achieve excellent vibration suppression effect,it is often necessary to have a large additional mass to satisfy.However,the nonlinear energy sink is a vibration suppression device attached to the system,and the high cost caused by the large additional mass restricts the application of the nonlinear energy sink in engineering.In order to overcome the drawbacks of traditional nonlinear energy sinks that rely on large additional mass,this dissertation proposes a new type of inertial nonlinear energy sink,which greatly reduces the mass of nonlinear energy sinks.The study of the inertial nonlinear energy sink and its suppression of structural vibration promotes and broadens the practical application of nonlinear energy sink,which has important theoretical significance and application value.Specific research contents are as follows:The first chapter clarifies the purpose and significance of the research,describes the research status of the nonlinear energy sink,inerter and nonlinear vibration isolation,and introduces the main research contents and innovations of this dissertation.In the second chapter,a new type of inertial nonlinear energy sink is designed by replacing the mass in the traditional nonlinear energy sink with the inerter,achieving a significant reduction in the mass of the nonlinear energy sinks.The nonlinear vibration reduction dynamical equations of the coupled inertial nonlinear energy sink system are established.By applying the harmonic balance method,the nonlinear forced vibration response of the system is predicted.By comparing with the traditional nonlinear energy sink,the advantages of using the inertial nonlinear energy sink are discussed.Furthermore,the influence of the parameters of inertial nonlinear energy sink on the amplitude-frequency response of the system is discussed,and the optimal range of parameters is determined.In the third chapter,a combined vibration damping scheme with both nonlinear vibration absorption function and nonlinear vibration isolation function is presented by combining the inertial nonlinear energy sink and the quasi-zero stiffness.When the vibration of the structure is isolated by the quasi-zero stiffness system,the smaller dynamic stiffness may cause large vibration of the system in the case of increasing the effective vibration isolation band width,which restricts the promotion of the quasi-zero stiffness isolator to engineering applications.This chapter explores the combination of nonlinear absorption and nonlinear isolation to improve vibration suppression efficiency.The dynamic model of the combined vibration damping system is established,and the harmonic balance method is applied to predict the system vibration displacement and force transmissibility.The vibration suppression performance of the combined vibration damping scheme was evaluated based on the suppression efficiency of the resonance and the effective vibration isolation bandwidth.By comparing with the quasi-zero stiffness isolation scheme and the inertial nonlinear energy sink damping scheme,the vibration suppression advantages of the combined vibration damping scheme are explored.In Chapter 4,the suppression of the transverse vibration of the elastic beams with multi-modal vibration characteristics by the inertial nonlinear energy sink is studied.To facilitate the realization in engineering,the inertial nonlinear energy sink is placed at the boundary of the beam.A dynamic model of discrete-continuous nonlinear coupling is established based on the generalized Hamilton principle.The approximate analytical solution for the steady-state response of multi-mode resonance of the elastic beam is obtained by combining the modal truncation and the harmonic balance method,and numerical verification is carried out.The results show that the inertial nonlinear energy sink has an high-efficiency damping effect on the transverse vibration of multiple modes of the elastic beam.Finally,the parameters of the damping system are optimized.In Chapter 5,the combined vibration damping scheme composed of the inertial nonlinear energy sink and the quasi-zero stiffness is introduced into the multi-modal transverse resonance suppression of the elastic beam.By comparing with the uncontrolled system,the influence of the combined vibration damping scheme on the natural frequency and the mode shapes of the transverse vibration of the elastic beam is studied.The vibration suppression effect of the combined vibration damping scheme for multiple modal resonance of the elastic beam is investigated by comparing the steady-state response of the transverse vibration of the elastic beam with or without the combined vibration damping device.Finally,the influence of the parameter of the inertial nonlinear energy sink on the vibration suppression effect of the combined vibration damping scheme is discussed.