Sheet molding compound applications for origami-inspired metamaterials

This thesis explores a low-cost, scalable manufacturing approach for an origami-inspired acoustic metamaterial by combining forged short-fiber carbon-epoxy composites with 3D-printed polymer molds. A Miura-Ori-based unit cell was chosen for its acoustic characteristics, and a complete workflow was developed: CAD modeling of the unit cell, design of multi-part molds for FDM production, iterative forging with chopped 6K carbon fibers and a room-temperature IN2 epoxy/AT30 hardener system, mechanical characterization, and a four-unit-cell scale-up demonstration. The process was refined across three iterations to address voids, fiber gaps, and compaction issues. The optimized procedure produced defect-free tensile test specimens that exhibited a predominantly linear elastic response in tensile testing. Results were benchmarked against Aluminum 5154-H36 specimens produced under the same test conditions, showing that the forged composite provides a favorable stiffness-to-weight ratio for non-primary aerospace components. A four-cell component was successfully fabricated, confirming scalability; minor defects observed in the multi-cell part were traced to pressure distribution and are addressable. The study demonstrates that 3D-printed molds and forged carbon-fiber processing represent a viable route for producing complex metamaterial geometries, offering rapid iteration, reduced tooling cost, and acceptable mechanical performance for applications such as acoustic inserts and interior aircraft panels.