Mode separation of a single-frequency bi-modal elastic wave pulse by a phononic crystal

Abstract

Multiple wave modes in a signal can be effectively separated by frequency filtering or frequency-based methods as long as the modes propagate at different frequencies. However, they cannot be applied for the separation of multiple modes that propagate at the same frequency. This work shows that two wave modes contained in a single-frequency bi-modal signal can be separated if a specially engineered phononic crystal (PC) is employed. For demonstration, guided elastic wave experiments were performed in a thin aluminum plate in the middle of which a PC is inserted for mode separation. (C) 2011 American Institute of Physics. [doi:10.1063/1.3662446