Study On Energy Transfer And Acoustic Radiation Characteristics Of Eccentrically Stiffened Plate

Stiffened plate structure is widely used in the field of ship and aerospace,and the research on the vibration energy transmission and acoustic radiation characteristics of the reinforced structure has been paid more and more attention in order to reduce the transmission and acoustic radiation of the vibrating energy in the structure.In this paper,from simple to complex,the dynamic characteristics of eccentric reinforcement,unidirectional stiffened plate and orthogonal stiffened plate are analyzed in sequence.Firstly,based on the wave method,the dynamic characteristics of single eccentric reinforcement under traveling wave excitation are analyzed,and the dynamic stiffness of eccentric reinforcement is obtained,which lays a foundation for the subsequent study of eccentric stiffened plate.There is a critical angle for the transformation of flexural waves into in-plane waves.When the incidence angle is close to the critical angle,a large amount of flexural waves are transformed into in-plane waves,and the influence of eccentricity cannot be neglected,which is very obvious in the parallel periodic stiffened plate.Then,the acoustic-vibration coupling equation of stiffened plate is established by Fourier transform and the eccentric reinforcement dynamic stiffness in the Wave number field,and the influence of the point excitation,the line excitation and the rectangular region excitation on the acoustic vibration characteristics is analyzed.The results show that the stiffened plate can be reduced to orthotropic plate when the plate bending wave is raised to 3 times of the spacing.And the influence of the reinforcement makes the plate flexural wave propagation in existence pass band and stop band,its distribution is affected by the relative stiffness of the reinforcement and the plate,and reveals the high radiation levels is due to the radiation circle pass band;When reinforcement stiffness is opposite bigger,there is about critical frequency wavenumber,reinforcement and greater than the critical frequency reinforcement will have a larger radiation caused particular direction,pressure,and contribution to the far field radiation of leading role,but the sound power level is still consistent with the equivalent model In addition,the position on the sound radiation intensity is very significant,the influence of strong incentive stiffness should be applied to large structure,and when the incentive area is greater than the acoustic wavelength can effectively reduce the radiation sound power.On the basis of this,the acoustic and vibration characteristics of the orthogonal stiffened plate are analyzed,and the acoustic radiation characteristics are the same as that of unidirectional stiffened plate.Under the same excitation,the effect of orthogonal stiffened plate on vibration transmission is better than that of unidirectional reinforcement,but the decrease of acoustic radiation power is smaller.