Mode Selection of Leaky Lamb Waves in Steel Plate

The dispersion and attenuation of Lamb and Leaky Lamb waves propagating in a 1 ㎜-thick steel plate wave investigated. For acquiring a long (or large) range inspection capability, the fundamental symmetric and anti-symmetric wave modes (SO and AO) aver lowe frequencies were studied. Based on the dispersion curves, as well as pitch-catch and multi-mode simulations, it was shown that the SO mode over low frequencies is the proper mode to minimize the dispersion and attenuation. In addition, it was shown that the SO mode couldbe easily distinguished under multi-mode simulation since it has a larger group velocity than the AO mode.