偏置磁场强度对交叉线圈式扭转导波换能器换能效率的影响

Effect of bias magnetic field strength on coupling efficiency of cross-coil torsional guided wave transducer

交叉线圈式带状磁致伸缩扭转导波换能器偏置磁场强度直接影响换能器换能效率,为获得较佳的检测效果,需要研究偏置磁场强度对该换能器换能效率的影响。首先,从磁致伸缩效应出发,分析交叉线圈式带状磁致伸缩扭转导波换能器的工作原理。其次,在模态验证实验的基础上,分别对激励和接收换能器换能过程中偏置磁场的作用进行研究。实验结果表明随着偏置磁场强度的增大激励端和接收端换能器换能效率均先增大后减小。最后进行缺陷检测实验,当激励端和接收端均选择最佳换能区域时,对比模态验证实验,缺陷信号明显增大。该研究结果可为换能器的现场应用提供技术支持。

Since the bias magnetic field strength directly affects the magnetostrictive patch torsion guided wave transducers'coupling efficiency,in order to obtain better detection results,it is necessary to study the effect of the bias magnetic field strength on the coupling efficiency.Firstly,according to the magnetostrictive effect,the principle of the magnetostrictive patch torsion guided wave transducers of crossed coils is analyzed.Secondly,based on the modal verification experiment,the effects of bias magnetic field in the process of excitation and receiving transducer transduction are studied.The experimental results show that the coupling efficiency of the excitation and receiver transducers increases first and then decreases with the increase of the bias magnetic field strength.Finally,the defect detection experiment is carried out.When the optimal transducing area is selected for the transmitter and the receiver the defect signal increases obviously compared with the modal validation experiment.The research results can support the field application of the transducers.