The slow zero order antisymmetric Lamb mode in phononic crystal plates.

In this paper, the group velocities of the zero order antisymmetric (A0) Lamb modes in a phononic crystal plate with single layer cylindrical holes parallel to the surface of the plate were investigated theoretically. The results show that by increasing the filling fraction, the A0 mode can be efficiently slowed down and the group velocity of the A0 modes can be tuned from the positive to the negative referring to the phase velocity. Moreover, the zero group velocity of the A0 modes can be obtained with a given filling fraction. These results may be useful in designing acoustic devices.