Design Of Underwater Particle Velocity Pickup Sensor

In the underwater sound field,the sound pressure and particle velocity are two important physical quantities that characterize the sound field.The acquisition of sound pressure value is using sound pressure sensor;and the acquisition of value of the particle velocity,the current widespread using of vector sensors.With the using of vector sensors in various areas of underwater acoustic more and more extensive and in-depth,its own shortcomings and shortcomings caused more and more attention and research.In this paper,on the basis of summarizing and analyzing the problems existing in the engineering application of classical pressure-gradient and co-oscillating vector sensors,a new method for picking up the velocity of underwater sound field was proposed.That is,according to the acoustic field in the sound waves from the water medium and into the elastomer,the elastic body built the new sound field and the relationship between the internal particle velocity and the velocity of the external water medium,and by using of vibration sensors to pick up its particle velocity information.According to the design of the underwater particle velocity pickup sensor to fundamentally solve the co-oscillating vector sensor in the design and application process,due to density ratio and flexible suspension of the restrictions and effects,but also has a higher sensitivity,smaller dimensions,easier application mode,and wider work band characteristics.Based on the analysis of the acoustic characteristics of underwater particle velocity pickup sensor,the principles of obtaining the information of the particle velocity in the water were given by theoretical calculation and simulation analysis.On this basis,by taking into account the influence of the preamplifier structure,the watertight cable structure,the sound pressure channel structure and the mounting bracket structure on the acoustic performance of the pickup sensor often encountered in engineering applications,the integrated design method of the underwater particle velocity pickup sensor was proposed by using the simulation method for the above problems.Aiming at the vibration disturbance caused by the platform of the pickup sensor,this paper put forward the design method of the vibration isolation structure between the pickup sensor and the application platform,and realized the anti-jamming ability of the underwater particle velocity pickup sensor in engineering applications.Firstly,this paper established the sound field model of underwater elastic sphere and cylinder,and deduced the expression of the relationship between the velocity of the internal particle of underwater elastic sphere and cylinder and the velocity of the water particle.Then some principles of material parameter selection in the design process of the pickup sensorwere given.This paper analyzed the influence of the geometrical parameters of the elastic sphere on the resonant mode frequency by finite element software,and gave some principles of geometrical parameter selection in the design process of the pickup sensor.Then,the sensitivity of the "principle sample" designed and produced by this principle was tested in the standing wave tube.Secondly,based on the analysis of the influence of the additional structure and the connection structure on the acoustic characteristics of the pickup sensor,according to the simulation optimization results,this paper gave the optimization principles of material parameters and geometric parameters of the practical pickup sensor sample,and tested their performance parameters in the standing wave tube.Thirdly,in order to improve the anti-jamming ability of the practicle pickup sensor sample,combined with the various vibration interference problems caused by the vector sensor in engineering applications,this paper designed single-stage and two-stage vibration isolation system based on rubber damper,and analyzed and summarized their advantages and disadvantages of the transmission characteristics theoretically.On this basis,the classical box model was used to simulate and analyze the shock state of the sensor and the array in the operation,and some principles of the selection of the parameters in the design process of the two-stage vibration isolation system were gave.In addition,the finite element simulation was used to analyze the influence of the resonant mode of the intermediate brackets on the transmission characteristics of the vibration isolation system.The results provided a reference and basis for the design process of vibration isolation system.Then,this paper carried out the vibration disturbance experiment in the silencer pool,and verified the effect of vibration isolation system on vibration signal and the accuracy of finite element simulation results.By comparing the test results of sensitivity and directivity of the pickup sensor sample,the effect of the vibration isolation system on the performance parameters of the pickup sensor was verified in different connection states.