Research On Mosaic Ring Transducer And Its Linear Array

According to the practical working requirements of small underwater unmanned vehicle(UUV),it is required to realize the acoustic emission of low and middle frequency band with ultra-small size and light weight.Aiming at this application background,this paper mainly uses the mosaic ring transducer assembled by the combination of active and passive materials to carry out the research of frequency reduction,weight reduction and high power transmission and array technology.Firstly,according to the resonant frequency formula of circular classical equivalent circuit,light weight,low sound speed and high strength passive materials should be selected for the application of ultra-small size,low frequency and light weight.By comparing the basic properties of several passive materials of mosaic ring transducers,PEEK(Polyether Ether Ketone)material was used as passive structural material for the study.The electromechanical equivalent circuit diagram of the ring transducer splicing PEEK strip and piezoelectric ceramic strip was derived,and the resonant frequency and electroacoustic performance parameters of the transducer were calculated according to the equivalent circuit diagram.The vertical directivity function of the inlaid circular array is derived based on the radiation field theory of the slender column.The directivity function of the inlaid circular vertical array with equal spacing is obtained by using the product theorem combined with the directivity function of the uniform line array of the element point source.Then,COMSOL finite element software was used to analyze the main vibration modes and characteristics of the mounted ring transducer,focusing on the influence of the proportion of active and passive materials,the mounted mode and the structure size on the response of the transducer’s emission voltage.According to the research results,the optimal design of the transducer was carried out,and the methods of reducing frequency,reducing weight and increasing radiant acoustic power were summarized.Compared with the full-ceramic mosaic ring transducer of the same size,the resonant frequency of the transducer using PEEK and piezoelectric ceramic mosaic ring transducer was reduced by 33.3%and the weight was reduced by 27.6%.Then,the finite element model of linear array is established,and the emission voltage response of array is simulated and analyzed.The spacing and number of array elements are optimized,and the parameters of the mosaic ring transducer array which can be used for small underwater unmanned vehicles are given,and its radiation performance is simulated.Finally,according to the simulation results,two prototype ring transducers were made and the performance test was completed.A single transducer has a maximum structural dimension diameter of 226 mm,height of 150mm and weight of 8.4kg,the resonant frequency in water was 2.5kHz,and the maximum transmitting voltage response value was 134.7dB.Using these two transducers as array elements,the actual prototype of the binary linear array is made.The measured resonant frequency in water is 2.6kHz,the maximum emission voltage response value is 139dB,and the maximum sound source level can reach 190dB.The results show that the transducer designed in this paper has the radiation characteristics of low frequency and high power under ultra-small size and light weight.It is concluded that using PEEK material and piezoelectric ceramic insert ring structure can greatly reduce the working frequency and weight of the transducer.