Multi-basic frequency combined SH0 model electromagnetic acoustic transducer

Abstract

The invention discloses a multi-basic frequency combined SH0 model electromagnetic acoustic transducer, belonging to the field of nondestructive detection. The multi-basic frequency combined SH0 model electromagnetic acoustic transducer is composed of a signal input BNC (Bayonet Nut Connector), a signal output BNC, a pulse electromagnet power supply BNC, a magnet fixing plate, a protective shell,a pulse electromagnet and a folded coil; the folded coil is put in a groove on the bottom of the protective shell; the pulse electromagnet is arranged in the protective shell; the magnet fixing plateis arranged on the pulse electromagnet; a cover plate of the protective shell is arranged at the uppermost end of the protective shell; and the signal input BNC, the signal output BNC and the pulse electromagnet power supply BNC are fixed on the cover plate. The signal input BNC and the signal output BNC are respectively connected into terminals on the upper and lower surfaces of the folded coil;and the pulse electromagnet power supply BNC is connected to a winding of the pulse electromagnet. Compared with an equivalent periodic coil EMAT (Electro Magnetic Acoustic Transducer), the transducer provided by the invention can pay attention to the information of a plurality of frequency points and can replace a plurality of EMATs with different frequencies to carry out frequency sweeping.

Description

technical field [0001] The invention belongs to the field of non-destructive testing, and in particular relates to a SH0 modal electromagnetic acoustic transducer (EMAT, Electromagnetic Acoustic Transducer) with multiple main frequency combinations. Background technique [0002] Horizontal shear wave (SH wave) is a kind of ultrasonic guided wave propagating in plate structure, and its propagation characteristics are very attractive in the aspect of guided wave detection. SH only vibrates in the shear direction parallel to the plate surface in the plate. When it encounters the reflection of the interface that is consistent with the vibration direction of its particle, the SH wave does not undergo mode conversion. In addition, the zero-order mode of the SH wave does not disperse, and the propagation speed is low, and it has high spatial resolution under the same instrument conditions. Therefore, SH wave is widely used in various defect detection of boards and structural healt...

AI Technical Summary

Problems solved by technology

This will make the sensor too bulky, and it will not be easy to move when the detection object is ferromagnetic material

[0011] The design of the above coils and magnets leads to the insufficiency of the commonly used SH wave EMAT in terms of received signal amplitude, time domain resolution and sensor flexibility.

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