摘要
采用有强磁化特性的磁性液体作为换能器中制动元件,实验建立一个交变的梯度磁场作用于磁性液体,通过压电陶瓷换能器检测到磁性液体振动而产生的声波,发现磁性液体在交变梯度磁场作用下有磁致伸缩效应。导出了磁性液体振动特性的动力学一般方程,揭示了交变的梯度磁场作用引起了交变的磁性液体的内压强,从而引起磁性液体的体积发生伸缩,产生机械振动,激励空气产生声波的机理。以磁性液体为制动元件可以研制较理想的大功率低频宽带声学发射换能器。
Ferrofluids with high magnetization property are used as braking element in transducer. Laid ferrofluids are in alternative magnetic field. And the signals are converted into electrical signals by piezoelectric ceramic transducer. Through the sound waves generated by magnetostrictive, vibration of ferrofluids can be detected. Ferrofluids in alternative magnetic field is discovered that it has magnetostrictive effect. By means of theoretical calculations and analysis, the commonly power mechanics equation formula of vibration character of ferrofluids is established. Internal pressure of alternating magnetic fluid is caused by mechanism-the action of alternative gradient magnetic field. It is brought that volume variation of ferrofluids which induce vibration and transmit sound wave in the air. Ferrofluids as braking element can develop the acoustic emission transducer with high power, low frequency and wide frequency response.
出处
《电声技术》
2009年第6期29-32,共4页
Audio Engineering
基金
浙江省科技攻关项目(2007C21025)
宁波市科技攻关项目(2007B10010)
关键词
换能器
机械振动
交变的梯度磁场
transducer
mechanical vibration
alternative magnetic field
