Abstract

High order ultrasonic guided wave modes have more and more applications in nondestructive testing. Controlling the excitation when working at frequencies above the cutoff of the first high-order mode is essential to reduce the complexity of the transmitted wave packet. Papers available in the literature demonstrated that single element transducer associated with an angled wedge could be used to excite high order guided wave modes at a chosen phase velocity corresponding to the wedge angle. Ultrasonic phased array probes typically used in ultrasonic imaging have variable beam steering capability through the control of the elementary delay law. This study investigates the possibility of exciting specific ultrasonic guided wave modes or group of modes at high frequency-thickness products using an ultrasonic phased array probe. The regions of the dispersion curves targeted can be controlled by the input signal bandwidth and the angle of the generated beam. The method of excitation and its theoretical background are described. Finite element simulations are presented to verify the analytical predictions and quantify the unidirectional and diffraction properties of the transmitted beam. Experiments show striking agreement with the finite element simulations including the possibility to excite a single mode in a narrow zone at high frequency-thickness products.

How to Cite:

Veit, G. . & Belanger, P. ., (2019) “An ultrasonic guided wave excitation method at constant phase velocity using ultrasonic phased array probes”, Review of Progress in Quantitative Nondestructive Evaluation .