基于电磁超声换能器的电磁声发射检测方法研究

Electromagnetic acoustic emission as a new type of nondestructive testing technology, electromagnetic loading of the metal artifacts can produce Lorentz force in the crack, thus stimulates the noise emission signal, which can realize active defects detection or to evaluate the damage degree of defects. Electromagnetic ultrasonic transducer (EMAT) is the core of electromagnetic ultrasonic technology, which can excite the ultrasonic wave in the skin layer of the metal component. Due to both of them through the principle of electromagnetic - stress coupling stimulates the ultrasonic in the metal component, therefore, this paper applies the EMAT electromagnetic loading device to the electromagnetic acoustic emission detection, constructed with output excitation signal, data acquisition, signal processing, data storage, and other functions in the integration of virtual instrument, the complete experimental system is set up, the experiment of aluminum sheet and plate specimen detection were carried out, by comparing the defect, hole and intact plate signal, the EAMT can be used for the detection of electromagnetic acoustic emission.