Influence of Architectural Scaling of Gyroid Lattices on the Coupled Acoustic and Mechanical Performance of Polyurethane‐Filled Interpenetrating Phase Composites

This study investigates Interpenetrating Phase Composites (IPCs) based on Gyroid Triply Periodic Minimal Surface (TPMS) architectures for multifunctional aerospace and automotive applications. Hybrid IPCs were developed by infiltrating 3D‐printed Gyroid lattices with moisture‐curing polyurethane foam. The research evaluates frequency‐dependent sound absorption and quasi‐static mechanical properties using experimental measurements and JCALP numerical modeling. The results demonstrate that reducing unit cell size enhances both stiffness and high‐frequency absorption. A critical synergy is identified at a 6 mm cell size, where foam infiltration increases sound absorption by 12.4% and shifts peaks toward lower frequencies. Mechanically, the IPC configuration provides a confinement effect that stabilizes the Gyroid struts against buckling. For the G04 architecture, Young’s modulus and specific energy absorption increased by up to 24.6% and 15.3%, respectively, relative to an equivalent‐mass unfilled Gyroid lattice with the same 4 mm unit‐cell size. Foam infiltration modified the acoustic response depending on the Gyroid unit‐cell size. Optical observations suggest a wall‐induced variation in foam cell morphology. The combined results demonstrate that changing unit‐cell size under constant wall thickness changes the overall architecture, including porosity and relative density, which collectively influence the acoustic and mechanical response, providing practical design guidelines for multifunctional lightweight structures.