Study On Vibration Suppression Of X-type And Stewart-type Vibration Isolation Systems

Structural vibration control is an engineering problem with a very wide range of applications,and has been widely used in engineering fields such as aerospace,mechanical engineering and civil engineering.Passive vibration isolation is one of the main vibration isolation technologies in structural vibration control.Because of its simple structure,easy implementation,low cost,good economy,high reliability,easy maintenance and no need for external energy input,passive vibration isolation structure has been widely used.Passive vibration isolation can be broadly divided into two categories: base vibration isolation and energy absorption vibration reduction.This paper focuses on base vibration isolation and energy-consuming and energy-absorbing vibration-damping technologies,and carries out the following work.In this paper,a new type of X-shaped structure is designed.This new type X structure is assembled of large and small X-shaped structures.The combination of these two X-shaped structures can significantly improve the nonlinear effect of the structure.The designability of the structure greatly improves the adjustability of the structure.The Hamilton principle is used to establish the motion equation of the new type X structure.Based on the harmonic balance method,the transmissibility is used to study the influence of structural parameters and material parameters on the vibration isolation frequency band and resonance amplitude of the structure.In addition,the simulation software Adams is used to verify the correctness of the theoretical solution.The research results show that the increase of the number of layers of the large X structure,the initial angle of the large X structure,and the arm length of the large X structure can play a role in improving the vibration isolation performance.Based on the excellent stiffness adjustability of the X-shaped structure,the X-shaped structures with different arm lengths are used as vibration absorbers and periodically installed on the beam to obtain a metamaterial beam.Using the spectral element method,the overall spectral stiffness matrix of the metamaterial beam is established,and then the motion equation of the overall structure is obtained.The frequency response curve of the metamaterial beam is calculated,and then the band gap characteristics of the structure are analyzed.The influence of structural parameters and material parameters on the structural band gap characteristics is studied.The results show that the band gap characteristic can be adjusted by the structural parameters.In addition,this paper also designs a multi-degree-of-freedom vibration isolator,a double-layer Stewart passive vibration isolation platform with a vibration absorber.The vibration isolator can achieve vibration isolation effects in three spatial directions.Through the simulation software Adams,the vibration isolation performance of the new Stewart passive vibration isolator is studied,the structural parameters of the vibration isolator are adjusted,and the rules of the vibration isolation performance is summarized.Compared with the double-layer Stewart platform without vibration dampers,the transmissibility of the proposed Stewart platform with vibration absorber is significantly reduced.The vibration isolation effect of the proposed platform is test by experiments and the accuracy of the theoretical results are verified.