Investigation of phased arrays for guided waves applications

Abstract

One of the main problems in a long-range ultrasonics is effective generation of a desired wave mode. The objective of this paper is investigation and optimisation of low frequency transducer arrays for excitation of Lamb waves for long-range ultrasonics applications. The different types and parameters of transducer arrays have been investigated. The investigations were performed using the finite difference method. The dependence of the generated signal amplitude versus the gap between elements has been determined. It was shown that most optimal distance is λ/4, where λ is the wavelength, but the delay time should be optimised for each particular case. It was demonstrated, that the optimal delay time between excitation instants of the array elements enables to increase efficiency of excitation.