Stiffness and Damping Properties of a Composite Beam Design

This work presents a characterization of dynamic mechanical properties of composite beams that were 3D-printed using fused filament fabrication. Two materials were used in the manufacturing process: a flexible material was used as filler of the hollow section (FilaFlex—Polyether-Polyurethane elastomer) while polylactic acid (PLA) polymer was used for the external wall of the beam. The main objective for such material integration is to enhance damping properties without compromising the overall stiffness. Dynamic mechanical analysis (DMA) was used to determine the inherent beam stiffness (storage modulus) and damping (tanδ), to assess the influence of void-filling volume fraction in the dynamic properties and therefore optimize the beam static and dynamic performance. At room temperature, it was shown that the introduction of low contents of flexible filling actually generated an increased in stiffness due to the changes the filament orientation to accommodate the filling material. Regarding the damping performance, it was proved that the introduction of filling enhanced internal friction. It was possible to optimize both stiffness and damping of the beam design by finding the most beneficial combination of these properties.