Dual-Function Infill Design in Fused Deposition Modeling for Mechanical and Acoustic Optimization

This study presents a novel origami-inspired infill design for additive manufacturing (AM) that simultaneously achieves desirable compressive strength and acoustic absorption, validated via fused deposition modeling (FDM). Conventional design approaches limited by the structural geometric design freedom often focus on mono functionality (e.g., mechanical, acoustical, optical, etc.), followed by multiple functional structure assembly, or achieving multi-functionality by using material composites. A Kresling-origami cellular architecture was introduced that achieves dual functionality through geometric control alone, demonstrating superior performance to standard infill patterns (Gyroid, Honeycomb, Grid). Parametric determination identified a 90° twist angle with alternating layer direction as the optimal configuration determined by mechanical and acoustic performance scores, yielding a 237.1 N/g strength-to-weight ratio (9-37% improvement over other standard infills) and sound absorption average (SAA) (SAA=0.36, peak α=0.68 at 3600 Hz). Experimental validation confirmed the design's mechanical robustness under compression and acoustic efficacy via impedance tube testing (2000-5000 Hz). Beyond fundamental performance gains, the presented infill shows strong potential for application in multifunctional sandwich shell structures, such as those used in submarines, enhancing both lateral load-bearing capacity and internal noise absorption. This work advances AM by demonstrating that complex, multifunctional performance can be achieved through principled geometric design rather than material heterogeneity.