Phased Array Design Concepts for Lamb Wave Mode Tuning

Abstract

Experimental tuning of guided wave modes can be performed to search the dispersion space for modes with optimal detection capabilities. An ability to tune to a mode with maximum flaw sensitivity is essential to effective guided wave inspection of plates. A variable angle beam and a comb transducer with variable spacing are two approaches to perform mode tuning. These approaches can be difficult to implement in an efficient manner. This study focuses on the development of a multi-channel phased array transducer system with the potential to electronically search the dispersion space. The phase velocity spectrum of the output of the transducer is computed theoretically to analyze mode excitation and determine the influence of parameters. Analysis of the phase velocity spectrum shows that mode selection and control can be optimized by maximizing the loading length as well as the number of elements.