V.N.Oliynik Antisymmetric waves in the system of two parallel rods periodically supported by rigid transverse barriers and connected with an acoustic medium |
Acoustic bulletin, Vol. 11 ¹ 2, (2008) |
| The paper deals with considering the possibility of antisymmetric harmonic wave propagation in the system of two elastic rods periodically supported by rigid transverse barriers. The volumes bounded by the rods and adjacent barriers were considered to be filled with an acoustic medium (gas), with rods performing an antiphase motion. With use of the Floquet method, the corresponding dispersion equation has been obtained and its roots have been analyzed. The wave, excited in such way, is an equivoluminal one, therefore, the internal acoustic medium plays the role of an equivalent mass. Hence, in this case the effective system elasticity parameter and corresponding wave propagation velocity are considerably lower than that occurring at the in-phase rod vibration, accompanying by volume deformations of the gas-filled cells. The obtained result allows the qualitative explanation of some experimental data concerning wave properties of gas-filled porous media, in particular, the parenchyma of the lung. |
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KEY WORDS: elasto-acoustic structure, the Floquet method, harmonic wave, volume and equivoluminal waves |
| TEXT LANGUAGE: Ukrainian |