Research On Deep-water,Free-Flooded,Broadband Class ? Flextensional Transducer

In military applications,Thetechnology in the acoustic quieting of submarines have great progress in recent decades,and lots of advanced submarines have been able to hide in the ocean noise.The surface of the submarine,covering with anechoic tile,makes it hard for sound waves which frequency is under 1 kHz to detect them effectively.Only relying on passive sonar detection can't already meet the needs of detecting submarines.Remote detecting submarines need to use active sonar to cooperate.Low frequency,high power and large working depth become known as remote active sonar research direction.Class ? flextensional transducer is a type of transducer which have the characters of low frequency,high power and small size.But class ?flextensional transducer also have the characters of low work-depth and narrow band.This paper proposed a new structure of three shell class ?flextensional transducer,made the transducer obtain the charactersof broadband and high work-depths and keep the characters of low frequency,high power and small size at the same time.This paper first introduced the development clss ? flextensional transducer and its characteristics,introduces the implementation method of low-frequency and broadband.And then put forward the ANSYS simulation solution for cavity vibration modal,and used new method to realize the stimulation of cylindrical cavity and oval liquid cavity with finite element software ANSYS.Then used ANSYS to establish the finite element modal of pure fluid cavity and pure cavity shell,and analyse the respective laws and the interaction law of each other.Then put forward the three shell class ? flextensional transducer,and the finite element mdal was established with ANSYS and analyzed the emission characteristic of the prototype and the liquid cavity.Design of the transducer is flooded,and the bandwidth is from 1.2 kHz to 2.8 k Hz,and the maximum transmitting voltage response level is 136.2 dB.Finally,the prestress analysis was carried out and the protoypre was made.Experimental measurement results shows that the bandwidth of the prototype is 1.1kHz to 3k Hz,the maximum of transmitting voltage response is 136 dB,the maximum sound source level is 197.5dB,and the results show that the theory and the test results are matched.Results show that the three shell design effectively reduces the influence of turbulent flow,and achieves high power launch under the condition of overflow,and effectively reduce the fluid cavity vibration modal frequency,andimproves the bandwidth.At the same time,it shows that the new ANSYS method is able to help design the fluid cavity of class ? flextensional transducer.