Topology-optimized ventilation barrier for mid-to-high frequency ultrabroadband sound insulation

An ultrabroadband ventilated acoustic barrier, composed of periodic subwavelength units (with a thickness of 50 mm), is put forward here by a density-based topology optimization method. We propose a unit with a cross channel as the initial unit for the topology optimization process. Compared with the initial one, the optimized barrier reduces the unit volume filling ratio by nearly 50 %. The efficient sound attenuation band is shifted to a lower frequency by nearly 665 Hz, and the broadband is broadened by nearly 870 Hz. Then, a simplification of the optimized unit is carried out, and the influence of the structure parameters on the acoustic attenuation performance is discussed. Numerical simulations and experiments are conducted to verify the sound-blocking performance. The optimized and simplified structures can block 90 % of the incident energy in [1420 Hz, 5140 Hz] and [1571 Hz, 5150 Hz], respectively, and both show excellent omnidirectional sound insulation performance. In addition, the ventilative capabilities are further evaluated by simulating the airflow across the two structures. The proposed barrier may provide new insight into the acoustic applications calling for soundproofing in free surroundings. (c) 2022 Elsevier Ltd. All rights reserved.