Research On Vibration Attenuation Of Ship Base Under The Arrangement Of Cladding Phononic Crystals

As the main platform for carrying power,the ship base must be able to withstand the serious impact of vibration generated by motor operation on the entire hull structure.Therefore,phononic crystals have been applied in some practical engineering as a new and effective vibration and noise reduction structure.The base connects the hull and equipment,not only fixing the equipment,but also serving as a key channel for vibration transmission of the equipment.The vibration generated by the equipment will pass through the equipment,isolation system,foundation,and hull,forming a complete chain system.However,due to the high difficulty and cost of processing and producing composite materials,as well as the difficulties in processing new vibration isolators and base structures,these studies are difficult to apply in engineering practice.Therefore,we need to develop a vibration damping structure that is easy to process and low in production cost,in order to apply it to the base.The development of such vibration reduction structures will provide new ideas and methods for the development of the field of base vibration reduction.Therefore,based on future development directions,laying phononic crystals on ship foundations can become an important research direction.By carefully designing phononic crystals,their outstanding performance can be fully utilized.The new damping structure is an important step towards efficiency,reliability,and sustainability in the shipbuilding industry.Therefore,the application prospects of phononic crystal materials in ship foundations are broad and worthy of further research and development.Firstly,this article studies three types of phononic crystal isolation pad structures for vibration reduction of ship foundations,namely the soft hard phononic crystal isolation pad wrapped in spherical scatterers,the soft hard phononic crystal isolation pad wrapped in spherical scatterers,and the soft hard soft phononic crystal isolation pad.By studying the band structure of phononic crystals,the corresponding complete band gap and band gap were obtained.Through modal analysis of each point in the band structure diagram,the vibration reduction principle of the band gap under this structure was clarified.Specifically,two modes corresponding to the beginning and end of the bandgap were studied to determine whether the vibration within the frequency range of the bandgap is suppressed,thereby achieving the purpose of vibration reduction.In addition,this article also explores the measurement of the bandgap of phononic crystals by changing the geometric and structural parameters of phononic crystals,which can be described by the starting and cut-off frequencies of the bandgap in the energy band structure diagram,as well as the corresponding bandgap width.At the same time,this article points out that in the mechanism of local resonance phononic crystal vibration reduction,material quality or stiffness,as well as corresponding structural parameters,will have an impact on the band gap,thereby affecting the vibration reduction effect.Finally,this article applies phononic crystal structures to the vibration reduction of ship foundations and conducts numerical calculations to study their vibration isolation performance.The experimental results indicate that both phononic crystal isolation pads without isolation systems and isolation platform structures have strong adaptability and significant low-frequency isolation effects.Among the three types of phononic crystal structures,the soft hard soft type phononic crystal structure has the best vibration isolation effect,achieving mid to low frequency isolation,expanding the vibration reduction frequency band,solving the problem of poor vibration reduction effect at mid to low frequencies of the base,and greatly reducing the vibration peak generated at low frequencies of the ship base.The research in this article has brought further improvements to the vibration reduction performance of ship foundations.In addition,the research in this article also has certain guiding significance for the design and optimization of phononic crystals.By analyzing the band structure of phononic crystals...