3D printed fibrous porous structures with enhanced noise reduction properties

Additive manufacturing allows the cost-effective fabrication of cellular porous structures with tailorable geometries. Structures with small pore sizes offer improved acoustical performance; however, they often result in increased structural weights and are difficult to produce using low-cost additive manufacturing methods. Here, we leverage our recent work demonstrating the fabrication of fibrous structures using 3D printing, to develop multifunctional porous structures with enhanced acoustical properties. Our method allows the addition of fibers to a structural host, which helps improve the acoustical performance without a significant weight or flow-reduction penalty. In this presentation, we outline the fabrication method and study the effect of adding fibers to the acoustical performance of porous structures with periodic gyroid unit cells. The effect of fibers on the acoustical impedance and flow resistance is studied using an impedance tube and a flow bench, respectively. We then use an inverse characterization method to analyze the effects of changing fiber and structural parameters on the acoustical performance. Our results show that adding fibers to porous host structures can drastically improve their broadband noise reduction potential.