Design And Test Analysis Of High Power Giant Magnetostrictive Transducer

As the international maritime rights and interests disputes intensify,all maritime powers have formulated more comprehensive plans for the development of underwater active detection systems to deal with the increasingly serious underwater defense issues.High-power electroacoustic transducers are the key to the underwater remote active detection system,the giant magnetostrictive materials which are the ideal material for manufacturing low frequency high power electroacoustic transducers have the advantages of large strain amount,large energy density,high electromechanical coupling coefficient and fast speed of response,etc.In this paper,a high-power lowfrequency transducer with a resonance frequency of 1000 Hz and a sound source level of 194 d B has been developed based on giant magnetostrictive materials.The research of the transducer is mainly from the following aspects:(1)Aiming at the requirements for energy efficient conversion of giant magnetostrictive transducers and low-frequency high-power emission,the combined magnetic circuit structure and mechanical structure of multiple rods are studied.The structure of the giant magnetostrictive longitudinal vibration transducer is optimized,including the design of rare earth giant magnetostrictive rod,the design of the front radiation head and the rear mass,the design of the central stress rod,the design of the multi-vibrator magnetic circuit,and AC Coil design and DC coil design and disc spring and prestress design,etc.Finally,based on the overall design structure of the giant magnetostrictive longitudinal vibration transducer,an experimental prototype has been fabricated.(2)Aiming at the inaccuracies of incomplete measurement methods of giant magnetostrictive material parameters at home and abroad,this article firstly proposes a measurement method for multiple axial magnetomechanical parameters including permeability,piezoresistive coefficient,compliance coefficient,etc,and builds a measurement platform for the axial magneto-machinical characteristic parameters of giant magnetostrictive materials.The axial magneto-machinical characteristic parameters of the material are extracted,and the correctness of the proposed method is verified by comparison with the measurement results of the resonance frequency method.Secondly,a giant magnetostrictive tangential characteristic parameter measurement platform is built,and the parameter fitting method is used to accurately extract the tangential magneto-machinical characteristic parameters of the material;Finally,combined with the measured axial and tangential characteristic parameters,finite element simulation is used to analyze and predict the impedance characteristics and sound source level of the designed transducer.(3)To verify the rationality of transducer design based on finite element simulation analysis,the experimental demonstration platforms are built.Firstly,the magnetic field measurement platform of the transducer is built,and the magnetic field distribution of the three magnetic circuit structures has been measured and analyzed under permanent magnet bias and DC coil bias,the test results verify the rationality of the magnetic circuit design;Finally,the transducer is tested for static displacement characteristics and dynamic displacement characteristics,and the electroacoustic emission performance test is carried out in the lake environment,the sound source level reaches 194 d B,and the test results verify the rationality of the transducer design.