线圈自激励电磁超声换能器设计及特性研究

发布时间：2018-04-26 04:02

本文选题：电磁超声 + 兰姆波　；参考：《机械工程学报》2017年16期

【摘要】：提出一种线圈自激励电磁超声换能器模型,该换能器无需磁铁提供静态磁场,可以避免磁铁对铁磁性材料吸附带来的不利影响,同时可以大大降低换能器质量。通过有限元仿真和试验结合的方法对所设计的换能器性能进行研究,随着提离距离提高,A_0兰姆波的衰减速率要快于S_0兰姆波,这是由于S_0兰姆波主要由磁致伸缩力引起的面内振动产生,动态磁场在6 mm提离距离时仍然具有较大水平分量。与之相比,A_0兰姆波主要由动态洛伦兹力引起,感应涡流强度及动态磁场强度在大于3 mm提离距离后都有明显衰减,动态洛伦兹力引起的面外振动衰减迅速。线圈自激励换能器可以在6 mm提离距离激励较纯净S_0兰姆波,优于传统换能器3 mm提离距离。最后,对两种兰姆波指向性进行研究,波长较长的S_0兰姆波具有更大的检测范围。
[Abstract]:A coil self-excited electromagnetic ultrasonic transducer model is proposed, which can avoid the adverse effect of magnet on the adsorption of ferromagnetic materials without the static magnetic field provided by the magnet, and at the same time greatly reduce the mass of the transducer. The performance of the designed transducer is studied by means of finite element simulation and experiment. The attenuation rate of the A _ 0 Lamb wave is faster than that of the S _ 0 Lamb wave with the increase of the lift distance. This is due to the fact that the S0 Lamb wave is mainly produced by the in-plane vibration caused by magnetostrictive force, and the dynamic magnetic field still has a large horizontal component when the distance is 6 mm. In contrast, the A0 Lamb wave is mainly caused by the dynamic Lorentz force, the induced eddy current intensity and the dynamic magnetic field intensity have obvious attenuation when the distance is larger than 3 mm, and the out-of-plane vibration induced by the dynamic Lorentz force attenuates rapidly. The coil self-excited transducer can excite the pure S _ S _ 0 Lamb wave at 6 mm lift distance, which is better than the traditional transducer 3 mm lift distance. Finally, the directivity of two kinds of Lamb waves is studied.
【作者单位】：北京科技大学高效轧制国家工程研究中心;北京科技大学钢铁共性技术协同创新中心;
【基金】：“十二五”国家科技支撑计划(2012BAB19B06) 教育部博士点基金(20120006110033)资助项目
【分类号】：TB552

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