DLP-Based 3D Printing of Low-Density Composite Formulations for Unit Cells for Mechanical Metamaterials

Mechanical metamaterials with tuned and functionally graded (FG) dynamic properties have potential for control of wave propagation in structures, as they exhibit dynamic behavior not normally observed in homogenous and natural materials. Along with the structure, the performance of metamaterials depends on the base material properties, specifically density and elastic modulus. DLP-based 3D printing has been shown as a promising technique to manufacture complex composite structures with high volume fraction of reinforcements, and which would be beneficial to achieve the required density and modulus. Commercially available resins enable good printing of complex structures; however, the resins are restricted in their intrinsic properties, which limits the design space of the metamaterials. This limitation motivates the development of new resin system that expands the design space of the metamaterial structures, thereby enhancing their performance. This paper focuses on DLP-based printing of preliminary metamaterial structures with an acrylate-based, commercially available resin (PR48), incorporation of low-density reinforcements into PR48, and discusses the need for modified formulations as greater filler concentrations are incorporated.