Synthetic phase tuning of guided waves

A novel method has been developed to generate and manipulate multi-mode gui ded waves. This technique uses a linear phased array whose elements are act ivated according to a prescribed time delay profile obtained from the dispe rsion curves. It is shown that a desired guided wave mode can be tuned by s ynthetically constructing a virtual wave from individually acquired wavefor m data. In addition to the development of such a synthetic phase tuning (SP T) technique, a pseudo pulse-echo (PPE) operation scheme is also developed for nondestructive testing. Experimental results are compared with those ob tained by more traditional techniques using variable angle wedges and array transducers. It was shown that the new technique is convenient, robust, an d flexible in utilizing multi-mode guided waves for nondestructive evaluati on (NDE). It is a dynamic method that can produce desired guided wave modes propagating in the desired direction without any mechanical alignment. The advantages and limitations of the technique are addressed.