【摘要】 为了实现电磁超声相控阵单通道激励下的平面波成像(PWI),提升检测效率，设计了一种新型电磁超声相控阵换能器，命名为子母共位电磁超声换能器(EMAT)。该换能器将激发线圈与接收线圈分离，激发线圈为整体线圈，接收线圈为分离多通道线圈，两类线圈共用一组磁体。该换能器可降低实验仪器操作复杂性，使得不需要相控阵全通道激发，采用单通道激励即可以实现电磁超声平面波成像。本文使用子母共位电磁超声换能器对“斜向排列”的2 mm直径阶梯横通孔缺陷进行成像检测，结果表明：常规平面波算法检测的纵向定位误差在0.5 mm范围内，横向定位误差在2 mm范围内，采用相位相干算法可辅助提升成像信噪比(SNR),表明该类型换能器对于平面波成像快速检测是适用的。更多还原

【Abstract】 In order to realize plane wave imaging(PWI)under single-channel excitation of electromagnetic acoustic phased array and improve detection efficiency, a new type of electromagnetic acoustic phased array transducer is designed, named as sub-parent common-position electromagnetic acoustic transducer(EMAT).The transducer separates excitation coil from receiving coil, the excitation coil is a monolithic coil, and the receiving coil is a separate multi-channel coil, and the two types of coils share a set of magnets.The transducer can reduce the operation complexity of the experimental instrument, so that the phased array full channel excitation is not required, and the electromagnetic ultrasonic plane wave imaging can be realized by using single channel excitation.A sub-parent common-position EMAT is used for imaging detection of the "oblique array" of 2 mm diameter stepped cross-hole defects.The results show that the longitudinal positioning error detected by conventional plane wave algorithm is within 0.5 mm, and the transverse positioning error is within 2 mm.The phase coherence algorithm can help to improve the imaging signal-to-noise ratio(SNR).It shows that this type of transducer is suitable for rapid detection of PWI.更多还原