Acoustic Black Hole Structures Using 3D Printed Polymer Concrete

Mitigating unwanted vibrations is critical for the safety and long-term performance of structural systems. Acoustic black holes (ABHs) provide passive vibration control by gradually reducing structural thickness, slowing flexural waves, and enabling wave attenuation. However, conventional geometric ABHs require extreme tapering, limiting structural integrity and large-scale application. Recent approaches using multi-material systems reduce wave speed through elastic modulus grading but lack sufficient stiffness and durability for load-bearing applications. This study introduces polymer concrete (PC) as a scalable material for 3D-printed ABH structures, offering tunable elastic properties through mix design. A 5-m coiled-path ABH was fabricated using normal concrete (NC), intermediate-modulus PC, and low-modulus PC to create a controlled stiffness gradient. Experimental flexural wave testing showed that the hybrid ABH reduced wave velocity by approximately 65% and improved attenuation by 220% compared to NC. These results demonstrate the potential of 3D-printed PC for large-scale, load-bearing vibration mitigation systems.