Evaluation of fatigue cracks by an angle beam EMAT–ET dual probe

• An EMAT–EC dual probe for fatigue cracks is proposed and designed based on angle beam EMAT.
• Capability of EMAT and ET operating modes are quantitatively evaluated.
• Mode complementarity of the dual probe on the sizing of cracks is demonstrated.

In this study, the authors propose an EMAT–ET dual probe for evaluation of fatigue cracks. The probe consists of a permanent magnet, a meander-line coil to emit and receive shear-vertical waves propagating obliquely in the material to be inspected, and a racetrack-shaped coil to pick up the ET signals. The experimental results show that the EMAT and ET modes of the proposed probe can detect and size both, shallow and deep cracks on the back side of specimens, respectively, which indicates that the proposed probe provides reliable evaluation of fatigue cracks within a wide range of depth values.