Sandwich meta-panel based on grooved corrugation for low-frequency sound absorption

In this work, a novel sandwich meta-panel (SMP) with grooved corrugations is proposed to efficiently attenuate low-frequency sound waves under deep subwavelength thickness (e.g., at 133 Hz). Most innovatively, SMP possesses tremendous mechanical characteristics (e.g., high bending stiffness) simultaneously, stemming from its corrugation core configuration. A theoretical prediction for sound absorption with an explicit expression of effective length is built, as well as a direct numerical simulation model. The theoretical and numerical results coincide well with each other, and demonstrate the SMPs' great capacity of manipulating low-frequency sound waves. Further, the SMPs can be tuned flexibly through altering perforation diameter, channel length and folding number, and multiple diverse unit cells can be coupled to get wide high-absorption bands (e.g., from 203 Hz to 249 Hz). The SMPs pave a new way for coiled-up space metastructures to engineering applications, with simple layout and perspicuous designing guidance.