We are delighted to announce that third year PGR Benjamin Pearce has won the Month 25 Presentation Prize- a £50 Amazon voucher. The Month 25 presentations are given each October, where the PGRs give a presentation on their work to date and feedback scores are given by their peers. Ben’s presentation was titled ‘Mode Interference and Directional Acoustic Stop Bands in Solid-Fluid Superlattices’. Please find the abstract below.
‘Mode Interference and Directional Acoustic Stop Bands in Solid-Fluid Superlattices’
Abstract:
Whilst there is a large amount of work on one-dimensional phononic crystals (superlattices) consisting of alternating layers of solid materials, there is comparatively little investigation of the properties of the equivalent solid/fluid system. These systems are predicted to exhibit a directional transmission response not available to solid/solid systems. This response stems from an interference between the symmetric and anti-symmetric modes of a submerged plate. This effect can lead to pronounced, angularly dependent reductions in transmission, for even a single solid layer submerged in fluid [1,2]. Extending this system from a single plate to a multilayer structure offers an interesting avenue for phononic crystal design [3]. Existing work largely neglects to consider the interaction of this interference with the Bragg modes of a such a periodic structure. Here we present a numerical and theoretical consideration of the effects of this interaction and how the choice of crystal geometry offers routes for the creation of large bandwidth directional stop bands.
References:
[1] M. Seiji, “Phononic Bandgaps Pecuiar to Solid-Fluid Superlattices,” Jpn. J. Appl. Phys, 2015.
[2] Z. Sai, X. Bai-qiang and C. Wenwu, “Controlling The Angle Range in Acoustics Low-Frequency
Forbidden Transmission In Solid-Fluid Superlattice,” J. Appl. Phys, 2018.
[3] S. Zhang, Z. Y, L. Wei, G. Hu, X. Bai-qiang and C. Wenwu, “Low Frequency Forbidden Bandgap
Engineering Via A Cascade of Multiple 1D Superlattices,” J. Appl. Phys, 2018.