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Updated: Jun 27, 2026

Characterizing Dissipative Elastic Metamaterials Produced by Additive Manufacturing
Published on: June 28, 2024
Characterizing the Anisotropic Elastic Properties of Auxetic Structures by Impulse Excitation Technique Combined with
Julian Rech1, Yuchen Leng2, Stefan Reinholz2
1Institute of Technology, Resource and Energy-Efficient Engineering, University of Applied Sciences Bonn-Rhein-Sieg, von-Liebig-Straße 20, 53359 Rheinbach, Germany.
None:
Auxetic metamaterials exhibit unique mechanical behavior due to their negative Poisson's ratio, but reliable determination of their effective elastic properties remains challenging. In this study, an experimental-numerical approach is proposed to characterize additively manufactured polylactic acid (PLA)-based auxetic sandwich structures. Material properties were first assessed using tensile testing, melt flow rate/volume rate (MFR/MVR) measurements, Fourier-transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), dilatometry, and nanoindentation, revealing stable mechanical behavior, good processability, and slight increases in crystallinity induced by the printing process. Impulse excitation technique (IET) measurements provided highly reproducible resonant frequencies, demonstrating a strong dependence on core geometry and orientation. However, classical ASTM-based evaluation yielded non-physical elastic properties, highlighting its limitations for architected metamaterials. Finite element modal analyses, combined with inverse parameter identification, enabled the determination of effective elastic properties using a transversely isotropic homogenized model. This approach significantly improved the agreement between experimental and numerical results. The findings revealed pronounced anisotropy and orientation-dependent auxetic behavior, including a negative Poisson's ratio for specific configurations. The proposed methodology provides a suitable framework for the reliable characterization and design of complex metamaterials.
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