Study On Sound Insulation Characteristics And Low Noise Structure Design Of Honeycomb Sandwich Panels

The composite of honeycomb sandwich structures has been widely used in aerospace and other fields, because of excellent sound insulation performance. It can not only be used as carriers, but also as noise insulations. The change of the structure parameters for the honeycomb sandwich panels has different affect in whole mechanics and sound insulation performance. So it has a great practical significance to study and analyze the mechanics and acoustics. In this paper, the natural frequency, sound insulation performance and low noise structure design based on the force radiation mode of the honeycomb sandwich plate were studied.Firstly, the influence of structural parameters on the natural frequency of sandwich plate had been analyzed by established the inherent frequency theory model of sandwich plate. The model of sandwich plate with natural frequency had been established by using the Reddy higher order shear deformation theory and the finite element method. Numerical simulation was used to calculate the first order natural frequencies of the sandwich plate. The accuracy of the theoretical model was verified, and the influence of some structure parameters on the natural frequency of the sandwich plate was be analyzed.Secondly, the influence of structure parameters on the transmission loss for the honeycomb sandwich panel was studied emphatically through theoretical modeling. Considering the harmonic sound wave vertical incidence, a honeycomb sandwich panel sound theoretical model was introduced with cellular characteristic impedance based on wave transmission theory and transfer matrix. Through accuracy analysis for the sound transmission theoretical model, the influence of the structure parameter for honeycomb sandwich plate panel thickness, core thickness and equivalent Young’s modulus to sound transmission loss was studied. By numerical analysis, the theoretical model is relatively simple, and the sandwich layer thickness, panel thickness and density of sandwich panel have a greater impact on the sound transmission loss.Finally, the sound transmission loss of the honeycomb sandwich plate had been calculated based on the force radiation modes. And the low noise structure design of the honeycomb beam was carried out by using the force radiation mode. The force radiation modes had be derived depending on the radiated sound power. The relationship between the radiation acoustic power and the force radiation mode had been established depending on the relationship between the radiation acoustic power and the external excitation, by the force radiation mode. A low noise honeycomb sandwich structure can be designed through adjustment of honeycomb core position in the radiation mode node or near the location. And the sound power transmission loss of honeycomb sandwich structure can be calculated using force radiation mode. Research results show that the radiation acoustic power of the whole structure will be the minimum when the honeycomb core was located on the force radiation mode node or near the node. And The sound transmission loss of honeycomb sandwich plates can be calculated based on the force radiation modes, and has higher calculating accuracy. The honeycomb sandwich structure with high sound insulation performance can be designed by using the concept of force radiation mode, which only needs to change the position of the honeycomb core, so as to achieve the purpose of low noise design of the honeycomb structure.