NiMnGa磁控形状记忆合金纵振式换能器

Longitudinal transducer driven by NiMnGa magnetic shape memory alloy

为实现低频、小尺寸水下声源,利用具有大应变、快速响应和高能量密度等优势的NiMnGa合金为驱动元件设计了水声换能器。基于NiMnGa合金变形原理,建立了NiMnGa纵振式换能器物理模型,推导了等效电路。通过有限元法,实现了NiMnGa纵振式换能器电磁-机械-声的多物理场耦合仿真,用于预测换能器的水下声学性能。制作了小型NiMnGa纵振式换能器样机,并在水中测试了500~800 Hz频带内的声源级。实验结果表明,换能器样机辐射面直径为8 mm,水中谐振频率为700 Hz,最大声源级为115.5 dB。

In order to realize a low-frequency and small-size underwater acoustic source,an underwater acoustic transducer has been designed by using NiMnGa alloy,which has the advantages of large strain,rapid response and high energy density.Based on the deformation principle of NiMnGa alloy,a physical model of a NiMnGa longitudinal transducer is established,and the equivalent circuit of the transducer is derived.Amulti-physics coupling model of electromagnetic,mechanical and acoustic fields is established by using the finite element method to predict the underwater acoustic performance of the transducer.A small-scale prototype of the NiMnGa longitudinal transducer is fabricated and its sound source level is tested in water within the frequency range from 500 Hz to 800 Hz.Experimental results demonstrate that the NiMnGa transducer with an 8 mm diameter of the radiation surface,achieves a maximum sound source level of 115.5 dB at 700 Hz.