Bioinspired auxetic metamaterial liners and sockets for transtibial prostheses: energy absorption and stress redistribution

Bodaghi, M ORCID: https://orcid.org/0000-0002-0707-944X, Jolaiy, S, Rahmani, K ORCID: https://orcid.org/0000-0002-0815-1562, Li, S, Gao, F and Zolfagharian, A, 2026. Bioinspired auxetic metamaterial liners and sockets for transtibial prostheses: energy absorption and stress redistribution. Journal of the Mechanical Behavior of Biomedical Materials, 175: 107305. ISSN 1751-6161

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Abstract

Prosthetic comfort depends on how the residual limb, liner, and socket share load. A crab-inspired auxetic metamaterial is introduced and applied to transtibial liners and sockets, with region-specific and fully auxetic variants benchmarked against conventional interfaces. Patient CT/3D scans guided anatomically targeted components. Auxetic lattices were additively manufactured in TPU (liners) and PA-12 (sockets). Cyclic compression experiments calibrated material models, and finite-element analyses quantified interface stresses and energy metrics. Across four sensitive liner regions, a four-zone auxetic TPU liner cut peak von Mises stresses by up to 60 %, and a fully auxetic liner by up to 65 %, relative to silicone/EL50 baselines. In sockets, a PA-12 design with two auxetic zones reduced peak stresses by ∼40–45 % versus ABS, while a fully auxetic socket achieved ∼80 % reductions with higher specific energy absorption. These findings indicate that bioinspired auxetics, integrated where anatomy needs compliance, improve pressure redistribution and mass-efficient energy management. The workflow from imaging to lattice design, printing, testing, and simulation was validated and is compatible with multi-jet fusion, enabling patient-specific prosthetic interfaces suitable for clinical translation.

Item Type:	Journal article
Publication Title:	Journal of the Mechanical Behavior of Biomedical Materials
Creators:	Bodaghi, M., Jolaiy, S., Rahmani, K., Li, S., Gao, F. and Zolfagharian, A.
Publisher:	Elsevier BV
Date:	March 2026
Volume:	175
ISSN:	1751-6161
Identifiers:	Number Type 10.1016/j.jmbbm.2025.107305 DOI 2545136 Other
Rights:	© 2025 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Divisions:	Schools > School of Science and Technology
Record created by:	Laura Borcherds
Date Added:	12 Dec 2025 16:12
Last Modified:	12 Dec 2025 16:12
URI:	https://irep.ntu.ac.uk/id/eprint/54869

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