A method of high efficiency ultrasonic excitation

The design of ultrasonic excitation pulse source is very important in health monitoring of structures. Traditional ultrasonic excitation pulse source generates high voltage by power amplification units, and it increases the volume of ultrasonic test instruments. In order to solve the problem and integrate the excitation source in virtual instruments, this paper presents a method to produce arbitrary wave based on high voltage pulse excitation and signal processing. A high efficiency ultrasonic excitation pulse source is designed by using high voltage DC source, RC discharge circuit and mercury relay. It can generate pulse signal with enough high voltage to guarantee excitation efficiency. The experiment demonstrates that the ultrasonic excitation pulse source can fully satisfy the requirement of the ultrasonic nondestructive detection. The response of the structure under test can be regarded as a wideband response. Wavelet transform is used to extract narrow band response from the original response. When the wavelet is designed as traditionally used burst wave, the transform result equals to the burst response. The effectiveness of this method has been verified by the test result. The device has the advantage of simple structure, energy efficient, high integration.