Impacts of the electromagnetic loading on the propagation of the ultrasonic wave

In recent years, the detectability of the nonlinear ultrasonic technology on the micro-damage has caused extensive concern. The key problem of the nonlinear ultrasonic technology was how to enhance the nonlinear acoustic response. For this purpose, this paper proposed a new method. The state of the metal closed-crack was changed by the eddy current loading. The ultrasonic had been modulated in the crack area which could produce the nonlinear ultrasonic phenomenon. Through analyzing the loading effects of the eddy current coil on the closed-crack and its dynamic behaviors, the impacts of the electromagnetic (EM) loading parameters on the ultrasonic nonlinear response were discussed. The ultrasonic nonlinear phenomena with the eddy current loading was studied by the modulated ultrasonic echo, and the corresponding relationship between the echo signal and the EM loading is demonstrated. It could provide the theory basis for engineering application of the nonlinear ultrasonic testing method.