High load-bearing plate-type metastructure for ultrabroadband sound insulation

Effective control of low-frequency noise has always been a global challenge. The emergence of sound insulating acoustic metamaterials provides a new approach to break the limitations of mass law at low frequencies. However, the practical application of metamaterials is limited by the challenge of balancing the characteristics of efficient low-frequency sound insulation and high load-bearing capacities. Although some existing metamaterials exhibit high load-bearing capacity and can break mass law in low-frequencies, the sound insulation bandwidth is typically narrow. In the present study, a high load-bearing plate-type metastructure (HLPTMS) for ultrabroadband low-frequency sound insulation is proposed. The HLPTMS is constructed by a periodic stiffened host plate and a flexible thin plate with strip mass blocks. Due to their inherent structural and acoustic coupling effects, ultrabroadband sound insulation performance and high load-bearing capacity are achieved simultaneously. To predict the sound insulation performance of the proposed HLPTMS efficiently, a semi-analytical method is proposed. The sound insulation mechanism of the proposed HLPTMS is further reveled. Through experimental measurement, the excellent ultrabroadband low-frequency sound insulation performance and the high load-bearing capacity of the HLPTMS have been confirmed. The proposed HLPTMS represents a novel metastructure with high load-bearing capacity and ultrabroadband low-frequency sound insulation performance, demonstrating promising applications in practical noise control engineering.