Lamb wave generation and reception with time-delay periodic linear arrays: a BEM simulation and experimental study

A time-delay periodic linear array model has been proposed for Lamb wave generation and reception in plates. The unilateral guided wave emitting and receiving have been achieved by applying the interference principle in the array designs. A hybrid BEM technique has been developed and applied to simulate the wave generation procedure with such arrays and to analyze the performance. Experimental results also are presented for two typical time-delay periodic arrays to qualitatively validate the theoretical designs. The effects of the array parameters on the array performance, such as the selectivity of Lamb modes and effectiveness of Lamb wave generation, are investigated through the 2-D phase velocity-frequency spectrum analyses as well as Lamb mode wave structure calculations.