Study On Vibration Characteristics Of Truss Structure With Periodic Oscillators

With the rapid development of China’s military forces,how to achieve the concealment of warships has become an important part.Reducing mechanical vibration and noise radiation is an important challenge for today’s environment.Floating raft is widely used in the field of ship vibration reduction,and it is an excellent vibration reduction equipment.In recent years,the concepts of local resonant phononic crystal,acoustic metamaterial and superstructure have been put forward,which provides a new idea for structural vibration reduction and noise reduction design.Phononic crystal and acoustic metamaterial are artificially designed periodic structures.In this paper,a truss structure with periodic oscillator is designed by using the band gap characteristics of periodic structure,and the periodic structure can suppress the vibration in a specific frequency range.By adjusting the structure form and size to change the position and bandwidth of the structure band gap,the structure in a specific frequency range can be realized the vibration reduction effect in a certain range.The main contributes are as follows:(1)Based on the principle of local resonance,a new truss structure with periodic oscillators is proposed,which has z-mode directional band gap.The band gap of the structure is calculated by finite element method,and the cause of the band gap formation is analyzed in detail.Then,the harmonic response analysis is carried out by COMSOL software,and the vibration transmission loss of the 6 × 6 periodic truss is calculated,which verifies the accuracy of the band gap calculation.(2)The influence of different structure size and vibrator weight on the energy band structure relationship is explored.The results show that with other parameters unchanged,the cell size increases,the start and cut-off frequencies of the band gap decrease,and the width of the band gap decreases;with the increase of the oscillator weight,the start and cutoff frequencies of the band gap decrease,and the width of the band gap increases.(3)The effects of different installation methods and numbers of oscillators on the band gap characteristics of periodic truss structures are studied.The horizontal,oblique,combined,longitudinal and interval installation modes of the vibrator are discussed.The final calculation results show that the band gap range of the inclined vibrator is larger than that of the horizontal vibrator,but the initial frequency of the band gap is also larger.With the increase of the number of the vibrator,the initial frequency of the band gap is basically unchanged,and the cut-off frequency will be significantly improved.The arrangement of every other line can greatly reduce the number of the vibrator The band gap width has little change.(4)A truss structure with adjustable preload and periodic vibrator is designed.The actual vibration reduction effect of three kinds of vibrator installation methods is tested.The test results show that the three kinds of vibrator installation methods have obvious vibration reduction effect within the band gap range.The truss structure with periodic vibrator designed in this paper has the effect of vibration reduction in a specific frequency range.The research content has a certain reference significance for the subsequent engineering structure design and application.