Vibration And Sound Radiation Control Of Stiffened Plates Based On Acoustic Metamaterials

The stiffened plate structure,featuring light and high rigidity,is widely used in the ship,aircraft,trains and other equipments.The vibration and noise of stiffened plates have been an important subject in the field of acoustics,mechanics,mechanical engineering and so on.At present,there are still some limitations of vibration and noise control,which need to be further explored.In recent years,the new concept and new principle of ? locally resonant acoustic metamaterials? in the field of acoustic physics provides a new idea to help solve the vibration and noise of the stiffened plate and other engineering structures.By exerting the locally resonant effect of the resonators,the work achieves the abnormal acoustic properties and the low frequency band gap properties.In accordance with locally resonant acoustic metamaterials,the research constructed a locally resonant structure by attaching a two-dimensional periodic array of spring-mass resonators on a traditionally engineering structure,like the bars,beams and plates.Researches have shown that locally resonant structure can produce significant flexural wave band gaps,can achieve efficient control of structure vibration and sound radiation and has broad application prospects.The paper,based on the widely requirements of vibration and sound radiation reduction of stiffened plates,constructs a locally resonant stiffened plate by attaching the two-dimensional periodic array of spring-mass resonators on a traditionally periodic stiffened plate.The study explores both band gap properties and vibro-acoustics properties.The main research contents and conclusions are as follow:1.Based on the finite element method and Bloch theorem,the calculation presents the flexural wave dispersion relations and forced vibration and sound radiation response of the locally resonant stiffened plate.The results are validated by comparing the predictions with simulations by FEM software COMSOL.2.The study investigates the properties of band gap and vibration reduction,which shows that over the band gap frequency ranges,the vibration of the locally resonant stiffened plate can be reduced remarkably.The analysis is given for the effects of the spring-stiffness,attaching location and mass ratio of local resonators on the flexural wave band gaps and those of vibration reduction properties,which can facilitate the design of the locally resonant stiffened plate for vibration-reduction applications in engineering.In addition,the differential evolution algorithm is used to optimize the multi-frequency band gaps of the locally resonant stiffened plate,which can achieve near-coupling featuring multi-band-gap to broaden the band gap.3.The investigation analyzes the sound radiation properties of locally resonant stiffened plates.It is found that the sound radiation of the structure is significant ly reduced in the band gap frequency range.The frequency,near the local resonant band gap,or in the higher frequency range,the sound radiation of the locally resonant stiffened plate also appears certain attenuation.Based on the optimization algorithm,further work optimizes the locally resonant stiffened plates characterizing multi-band gap under the damping effect of the spring,performing detail investigations for the broadband acoustic radiation suppression.In summary,this paper systematically studies the band gap,vibration and noise reduction properties of the locally resonant stiffened plates,and finds many meaningful phenomena and band gap tuning rules,which paves a road for the development of the vibration and noise control of the stiffened plate in engineering.