Session: ASME Undergraduate Student Design Expo

Paper Number: 179206

Experimental Validation of Cycloidal Metamaterial Geometries via Additive Manufacturing and Tensile Testing 

Mechanical metamaterials have gained significant attention for their ability to achieve tailored properties through carefully engineered microstructures rather than constituent material composition. Among these, lattice shells composed of curved fiber networks—such as the cycloidal arrangements proposed by Giorgio (2021)—offer promising routes to high compliance, tunable stiffness, and unique failure modes. While prior work has focused primarily on nonlinear continuum modeling and finite element simulations, there remains a lack of experimental validation to demonstrate the manufacturability and mechanical performance of such geometries under realistic conditions. Establishing this connection between theory and experiment is critical for confirming the predictive accuracy of simulation frameworks and assessing the practical feasibility of metamaterial design. Additive manufacturing, particularly 3D printing, enables direct physical realization of these complex architectures, allowing researchers to evaluate printability limits, defect formation, and structural fidelity.

This work presents an experimental investigation into the tensile behavior of 3D printed cycloidal metamaterial specimens, with the objective of validating the geometric advantages predicted in simulation. Specimens were fabricated using fused deposition modeling (FDM) in polylactic acid (PLA), flexible thermoplastic polyurethane (TPU), and stereolithography (SLA) with photopolymer resin, thereby spanning a range of stiffness, ductility, and brittleness. Test coupons replicated the cycloidal orthogonal fiber arrangement described in Giorgio’s formulation, while printing constraints were addressed to ensure geometric fidelity, dimensional accuracy, and consistent structural performance across all manufacturing techniques and material systems evaluated in this study.

Static uniaxial tension-to-failure experiments were conducted using a universal testing machine, with displacement-controlled loading and in-situ imaging to show deformation states along loading. Results show clear evidence of the characteristic deformation modes predicted in simulation, including localized out-of-plane buckling and distributed energy storage across fiber families. Comparison with numerical predictions confirms that the cycloidal topology enhances elastic strain accommodation relative to straight lattice counterparts, and preserves structural integrity beyond the onset of local buckling.

These results provide one of the first systematic experimental demonstrations of cycloidal lattice metamaterials produced via additive manufacturing. The findings highlight both opportunities and limitations in translating theoretical geometries to printed structures, particularly with respect to process-dependent defects and scale sensitivity. Beyond validating the model, this study establishes a practical basis for tailoring material selection and geometry in the design of compliant architectural structures. Future work will extend to cyclic loading and shear testing to further probe durability and multifunctional applications.

This contribution bridges simulation and experiment, providing essential validation for the mechanical potential of cycloidal metamaterials and advancing their transition toward engineering deployment.

Presenting Author: Samantha Lebsack University of Southern Maine

Presenting Author Biography: Samantha "Sadie" Lebsack is a 3rd year Mechanical Engineering Undergraduate Student at the University of Southern Maine, where she conducts research in the Composites Engineering Research Laboratory focusing on experimental validation of 3D-printed cycloidal lattice metamaterials. She has held engineering internships at NASA Goddard Space Flight Center, IDEXX Laboratories, and SharkNinja, gaining experience in cryogenics, product development, and mechanical design. Beyond her technical work, she is the founding president of the University of Southern Maine’s Society of Women Engineers section, where she leads initiatives to support women in STEM through mentorship and professional development.

Authors:

Samantha Lebsack University of Southern Maine
Tymur Sabirov University of Southern Maine
Ivan Giorgio University of L’Aquila
Milad Shirani Department of Biomedical Engineering, Yale University
Drew Sfirri University of Southern Maine
Asheesh Lanba University of Southern Maine