A multifunctional metastructure with energy dissipation and low-frequency sound-absorption optimized for decoupling by genetic algorithm

•A decoupled multifunctional metastructure design framework with excellent acoustic and energy absorption properties is proposed.•The energy absorption properties of this meta-structure have been investigated, which can be used to guide the design of acoustic absorption properties.•By means of a redesigned genetic algorithm the acoustic properties of this meta-structure are made insensitive to changes in the absorbing cavity.•The acoustic absorption coefficient of the metastructure is made to be greater than 0.9 in the range of 205–275 Hz before and after compression by coupling first- and second-order structures. A multifunctional metastructure has been proposed with the aim of having both energy-absorbing and sound-absorbing capabilities through the use of a rubber-filled re-entrant honeycomb frame. The acoustic and mechanical properties of the metastructure are decoupled utilizing a genetic algorithm so that the properties can be designed separately. The re-entrant honeycomb frame has the role of energy absorption, while the rubber filling allows the structure to form a Helmholtz-type absorbing material. The form of deformation of the structure under quasi-static compression is investigated by means of experiments and simulations, which are used to determine the variation of the cavity volume with compression. With the optimization by genetic algorithm, the first-order and second-order acoustic structures with excellent acoustic performance before and after compression have been obtained. At the same time, a continuous broadband sound- and energy-absorbing metastructure has been produced by combining these two structures. This work provides a remarkably new strategy for the integrated design of sound- and energy-absorbing structures and has a significant prospect for engineering applications such as aerospace engineering.