Bio-Inspired Suture Joints Enable Tuned Load Transfer in Digitally Fabricated Timber with Hybrid Thermoplastic Connectors.
9 affiliations
- 1Master Program in Engineering Sciences, Faculty of Engineering and Sciences, Universidad de La Frontera, Temuco 4811230, Chile.
- 2R&D Innovation Department, Eagon Lautaro S.A., Ruta 5 Sur Km 644, Lautaro 4860000, Chile.
- 3ArGEnCo Department, University of Liège, 4000 Liège, Belgium.
- 4Facultad de Arquitectura, Construcción y Medio Ambiente, Universidad Autónoma de Chile, Temuco 4810101, Chile.
- 5Escuela de Construcción Civil, Facultad de Ingeniería, Universidad de Valparaíso, General Cruz 222, Valparaíso 2341266, Chile.
- 6Faculty of Engineering and Sciences, Universidad de La Frontera, Temuco 4811230, Chile.
- 7Construction Multidisciplinary Research Group, Facultad de Arquitectura, Construcción y Medio Ambiente, Universidad Autónoma de Chile, Talca 3460000, Chile.
- 8Department of Mechanical Engineering, Universidad del Bío-Bío, Concepción 4081112, Chile.
- 9Department of Mechanical Engineering, Universidad de La Frontera, Temuco 4811230, Chile.
Abstract
Nature employs complex interlocking geometries, such as vertebrate cranial sutures, to combine load transfer with localized compliance and geometric interlocking. These biological interfaces incorporate alternating wide regions and narrow necks that can accommodate localized deformation while maintaining mechanical interlocking. Inspired by these structural characteristics, digitally fabricated timber systems-such as Skylark-WikiHouse assemblies-can employ analogous bow-tie joint geometries to introduce controlled compliance into the connection. While conventionally manufactured from plywood, the translation of this bio-inspired geometry using hybrid thermoplastic-timber materials remains insufficiently explored. To address this gap, hybrid bow-tie joints comprising 18 mm radiata pine plywood panels and compression-molded polypropylene (PP) or high-density polyethylene (HDPE) connectors were evaluated. Ten joints underwent displacement-controlled monotonic tension at 2 mm/min. The results indicate that PP and HDPE joints achieve nearly identical mean maximum loads of 6.61 and 6.65 kN, respectively. However, substituting PP with HDPE significantly alters the global load-displacement response, yielding 33% lower global stiffness, 63% greater displacement at maximum load, and 70% greater external mechanical work. Post-test examinations revealed that final visible cracking was localized to the surrounding plywood, with no complete rupture of the thermoplastic connectors. This final damage localization is consistent with the intended suture-inspired design concept; however, the present post-test observations do not establish the temporal sequence of crack initiation and propagation or directly demonstrate crack arrest. These findings identify connector material as a practical bio-inspired design variable for tuning the global stiffness-deformation response of digitally fabricated timber joints while maintaining comparable maximum tensile load capacity.
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BibTeX
@article{sandoval2026bioinspired,
title = {{Bio-Inspired Suture Joints Enable Tuned Load Transfer in Digitally Fabricated Timber with Hybrid Thermoplastic Connectors.}},
author = {Moisés Sandoval and Carlos Fierro and Geral Moreno and Javier Vidal-Barraza and Juan Pablo Cárdenas-Ramírez and María-José Castilla and Rodrigo Cancino and Rodrigo Valle and César Garrido and Víctor Tuninetti},
journal = {Biomimetics (Basel, Switzerland)},
year = {2026},
month = oct,
doi = {10.3390/biomimetics11100757},
url = {https://europepmc.org/article/MED/42930309},
note = {CC BY},
}
RIS
TY - JOUR
TI - Bio-Inspired Suture Joints Enable Tuned Load Transfer in Digitally Fabricated Timber with Hybrid Thermoplastic Connectors.
AU - Moisés Sandoval
AU - Carlos Fierro
AU - Geral Moreno
AU - Javier Vidal-Barraza
AU - Juan Pablo Cárdenas-Ramírez
AU - María-José Castilla
AU - Rodrigo Cancino
AU - Rodrigo Valle
AU - César Garrido
AU - Víctor Tuninetti
PY - 2026
DA - 2026/10/20
JO - Biomimetics (Basel, Switzerland)
DO - 10.3390/biomimetics11100757
UR - https://europepmc.org/article/MED/42930309
AB - Nature employs complex interlocking geometries, such as vertebrate cranial sutures, to combine load transfer with localized compliance and geometric interlocking. These biological interfaces incorporate alternating wide regions and narrow necks that can accommodate localized deformation while maintaining mechanical interlocking. Inspired by these structural characteristics, digitally fabricated timber systems-such as Skylark-WikiHouse assemblies-can employ analogous bow-tie joint geometries to introduce controlled compliance into the connection. While conventionally manufactured from plywood, the translation of this bio-inspired geometry using hybrid thermoplastic-timber materials remains insufficiently explored. To address this gap, hybrid bow-tie joints comprising 18 mm radiata pine plywood panels and compression-molded polypropylene (PP) or high-density polyethylene (HDPE) connectors were evaluated. Ten joints underwent displacement-controlled monotonic tension at 2 mm/min. The results indicate that PP and HDPE joints achieve nearly identical mean maximum loads of 6.61 and 6.65 kN, respectively. However, substituting PP with HDPE significantly alters the global load-displacement response, yielding 33% lower global stiffness, 63% greater displacement at maximum load, and 70% greater external mechanical work. Post-test examinations revealed that final visible cracking was localized to the surrounding plywood, with no complete rupture of the thermoplastic connectors. This final damage localization is consistent with the intended suture-inspired design concept; however, the present post-test observations do not establish the temporal sequence of crack initiation and propagation or directly demonstrate crack arrest. These findings identify connector material as a practical bio-inspired design variable for tuning the global stiffness-deformation response of digitally fabricated timber joints while maintaining comparable maximum tensile load capacity.
SN - 2313-7673
ER -