Fig. 6: Unidirectional Lamb-wave focusing at different frequencies.
From: Unidirectional focusing for broadband Lamb guided wave based on mode conversion
Simulated displacement amplitudes in the forward (a–d) and backward (e–h) cases at frequencies of 251 kHz, 291 kHz, 315.5 kHz, and 345 kHz. Note that 291 kHz corresponds to the transmission valley of the unidirectionally-transmitted elastic meta-atoms (UTEM). i–l are correspondingly simulated (lines) and measured (hollow symbols) displacement field profiles along the white dashed lines. For comparison, the normalized absolute amplitudes ∣w∣ at the same position of a bare plate without any grooves are presented by black dash dotted lines.
