Design Simulation And Test Of New Type Pressure-gradient Vector Hydrophone

Traditional hydrophones generally convert the received pressure into voltage through piezoelectric ceramics,and have no directional sensitivity.With the in-depth development of underwater detection technology,vector hydrophones with directional sensitivity are more widely used,but the internal structure is complex and the cost is high.In this thesis,through the structural improvement of the piezoelectric composite rod transducer and piezoelectric circular tube transducer,the simple structure of the scalar hydrophone and the signal processing algorithm are used to realize the estimation of the sound source orientation,which has the advantages of simple structure and low cost.The piezoelectric composite rod type differential pressure vector hydrophone and piezoelectric circular tube differential pressure vector hydrophone proposed in this thesis are based on the piezoelectric composite rod type hydrophone and piezoelectric circular tube differential pressure vector hydrophone.The structure is improved,and its piezoelectric ceramics are divided into four quadrants and eight quadrants respectively.According to the difference of the response voltage of each quadrant of the hydrophone,the time to generate the response voltage is different.The scalar information of the underwater sound field received by a single sensor is combined with the signal processing algorithm to estimate the azimuth angle of the incident sound wave.The piezoelectric composite rod-type differential pressure vector hydrophone can estimate the azimuth angle of the axial half-space sound source,and the piezoelectric circular-tube differential pressure vector hydrophone can estimate the azimuth angle of the circumferential fullspace sound source.The pressure difference vector hydrophone is combined to form a system,which can estimate the azimuth angle of the sound source in the whole space.Firstly,by deriving the theoretical models of the piezoelectric composite rod-type differential pressure vector hydrophone and the piezoelectric circular tube differential pressure vector hydrophone,the admittance is analyzed,the resonant frequency of the hydrophone is determined,and the working frequency.The Mason equivalent circuit of the piezoelectric composite rod-type differential pressure vector hydrophone is theoretically deduced,and its resonance frequency is calculated to be about 21 k Hz.It can be preliminarily determined that its operating frequency should be lower than 21 k Hz.By deriving the theoretical model of the film of the piezoelectric circular tube,the radial resonance frequency and the axial resonance frequency are analyzed as 27.4k Hz and155 k Hz,respectively.It can be preliminarily determined that the operating frequency should be much lower than 27.4k Hz.Secondly,the finite element method is used to simulate the designed piezoelectric composite rod-type differential pressure vector hydrophone and piezoelectric circular tube differential pressure vector hydrophone.And analyzing the simulation results,it is found that the maximum value of the sum of the response voltages in the adjacent two quadrants of the piezoelectric ceramic will show a regular change with the change of the azimuth angle of the incident sound wave,and it is normalized,and then fitted by MATLAB,Obtain the fitting formula.The calculated azimuth angle is obtained by calculating the response voltage obtained by the simulation and the fitting formula.The errors between the calculated azimuth angle and the real azimuth angle of the two new differential pressure vector hydrophones are within ±2°,which verifies that the fitting formula is feasible.Finally,the prototypes of the piezoelectric composite rod-type differential pressure vector hydrophone and piezoelectric circular tube vector hydrophone are made.Through the pool experiment,the experimental data is compared with the simulation data,and the fitting formula is combined to verify the piezoelectric composite rod.Reliability of Azimuth Estimation of Incident Sound Waves by the new type pressure-gradient vector hydrophone.The two new type pressure-gradient vector hydrophones designed in this thesis can reliably estimate the azimuth angle of the incident sound wave without any prior conditions,and the error can be controlled within a certain range.