Lamb wave mode isolation in isotropic metal plates

Lamb wave mode isolation in isotropic metal plates

Marcel Szczech

2025

Professor Rachel Edwards

Lamb waves are used in non-destructive testing of materials, often to identify and characterise defects. Electromagnetic acoustic transducers (EMATs) have the advantage over traditional piezoelectric transducers that they do not require couplant and can be used at higher temperatures, however using unphased comb EMAT arrays only allows the generation of one set of Lamb wave modes per array geometry. Using phased comb EMAT arrays on a plate allows generation of a variety of single lamb wave modes via an adjustable adjacent-EMAT time delay. A time-delay dependent excitation spectrum for a general EMAT phased comb array was programmed and verified experimentally for a 4 EMAT phased comb array used to generate Lamb wave modes on an ~8.109mm isotropic aluminium plate.

Lamb waves, phased EMAT array, mode isolation, comb EMAT array, phasing