Teaching-learning-based optimization of a composite metastructure in the 0-10 kHz broadband sound absorption range.

This paper proposes a strategy to broaden the sound absorption region of porous materials by embedding ribs. The theoretical solution and the numerical simulations of the optimization model show that the composite metastructure exhibits ultra-wide high absorption characteristics and an average sound absorption coefficient of 0.937 in the 0-10 kHz range upon its teaching-learning-based optimization. High sound pressures are present only among the embedded ribs. A significant slowing down of the sound takes place inside the metastructure. The impedance tube test confirms the design of the broadband sound absorption region in agreement with the teaching-learning-based optimization method.