Papers by Keyword: Underwater Acoustics

Abstract: The paper presents some results of multi-objective optimization for the multilayered membrane-type piezoceramic MEMS based transducers with perforated active PZT and intermediate diaphragms, covered by the protective plates, and a vacuum chamber. An influence of the protective plate elastic and viscous properties, the dimensions and the relative areas of the perforated holes on the sensitivity’s frequency response of the hydrophone was studied for the broadening and equalizes the operating frequency band. We optimize the key design’s parameters using the Pareto approach with the finite element (FE) model of coupled piezoelectric-acoustic problem for the hydrophone.

Abstract: Based on the modal superposition method, the analytical model of vibration and sound radiation from submerged double cylindrical shells with damping layers was presented. The shells were described by the classical thin shell theory. The damping layers were described by three-dimensional viscoelastic theory. The annular plates, connecting the double shells, were analyzed with in-plane motion theory. For different drive locations of radial point force on the inner shell, the sound radiated power and the radial quadratic velocity of the model were calculated and analyzed. The results show that making the drive location near the annular plate helps to reduce the sound radiated power and radial quadratic velocity of model, and making the drive location far from the middle of model also helps to reduce the sound radiated power. The drive applied on the location of annular plate causes high similarity of vibrations from inner shell and outer shell.

Abstract: The vibration and sound radiation from submerged cylindrical shell with double damping layers are presented. The cylindrical shell motion was described with classical thin shell theory. The double damping layers motion was described with the Navier viscoelasticity theory. For different Youngs modulus parameters of double damping layers, the sound radiated power and the radial quadratic velocity of cylindrical shell models were calculated and analyzed. The results show that the sound radiated power and radial quadratic velocity are reduced to varying degrees due to double damping layers in a large frequency domain except low frequency. The double damping layer with soft inner layer and hard outer layer can make the sound radiated peaks move to high frequency, can help to reduce the radial quadratic velocity on outer surface of damping layer, and can help to reduce the vibration of model at antiresonance frequency.

Abstract: This paper presents some results of finite element (FE) analysis performed for membrane-type piezoceramic transducer for underwater acoustics applications. We studied the miniaturized sensor with perforated holes in the active PZT membrane, intermediate, and protective plates. In this investigation an influence of the polyimide plate viscous damping, the membranes dimensions and the relative area of the perforated holes on the frequency response of sensitivity was studied for the broadening and flattening the operating frequency band. An optimization of these key parameters using the genetic algorithm working with the device’s FE model was demonstrated.

Abstract: Study on new absorption materials is important to the sound stealth of targets underwater. The simpler formulae of calculating multiple-layer absorption model is educed with transferring matrix. By numerical simulating, the relation between model’s acoustic characteristics and material parameters of each layer is provided.The study shows that a better performance is acquired when material Young’s modulus changed dynamically with frequency by a certain rule. On these basises, simulation contrast of the absorbing performances between styrene-butadiene rubber(SBR) and Spray Poiyurea Elastomer(SPUA) was carried out. The simulating result and the experiment provided that SPUA has good performance.