Abstract

Fused filament fabrication of foamed PLA enables lightweight structural parts with adjustable density and stiffness. This material expands during printing, making it ideal for functionally graded materials. It can serve as a sandwich core, enhancing lightweight properties. These panels can be a promising type of panel, as their behavior, such as vibracoustic, can be customized. However, their effectiveness in vibration attenuation remains unexplored. This study designs, manufactures, and tests 3D-printed foamed PLA sandwich panels with variable stiffness and density to improve vibroacoustic performance. The material’s Poisson’s ratio and elasticity modulus were characterized as a function of density, controlled by hot-end temperature and extrusion flow rate. A finite element model with spatially variable mechanical properties was developed for optimization. A genetic algorithm determined the optimal core properties to maximize the first two natural frequencies of a plate with one fixed edge and three free edges. The best designs were fabricated and tested, showing significant increment in the first two natural frequencies. This work advances the design and manufacturing of 3D-printed foamed PLA sandwich panels and contributes to high-performance, functionally graded components for enhanced vibroacoustic behavior.