Transition of deformation modes from bending to auxetic compression in origami-based metamaterials for head protection from impact

Abstract For the protection of the human head by energy absorption structures, a soft mechanical response upon contact with the head is required to mitigate the effect of impact, while a hard mechanical response for highly efficient energy absorption is required to stop the movement of the head. Thi...

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Main Authors: Sunao Tomita, Kento Shimanuki, Shin Oyama, Hidekazu Nishigaki, Toshiaki Nakagawa, Masakazu Tsutsui, Youhei Emura, Masahiko Chino, Hirokazu Tanaka, Yoshinobu Itou, Kazuhiko Umemoto
Format: Article
Language:English
Published: Nature Portfolio 2023-07-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-023-39200-8
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author Sunao Tomita
Kento Shimanuki
Shin Oyama
Hidekazu Nishigaki
Toshiaki Nakagawa
Masakazu Tsutsui
Youhei Emura
Masahiko Chino
Hirokazu Tanaka
Yoshinobu Itou
Kazuhiko Umemoto
author_facet Sunao Tomita
Kento Shimanuki
Shin Oyama
Hidekazu Nishigaki
Toshiaki Nakagawa
Masakazu Tsutsui
Youhei Emura
Masahiko Chino
Hirokazu Tanaka
Yoshinobu Itou
Kazuhiko Umemoto
author_sort Sunao Tomita
collection DOAJ
description Abstract For the protection of the human head by energy absorption structures, a soft mechanical response upon contact with the head is required to mitigate the effect of impact, while a hard mechanical response for highly efficient energy absorption is required to stop the movement of the head. This study realized the opposite mechanical properties during head protection by transitioning the deformation mode from bending to auxetic compression. First, non-linear finite element (FE) models were constructed to numerically reproduce the bending behavior. The calculated force responses agreed well with forces in bending tests. Using the FE models, the EA structures with proper transition of deformation modes were designed and installed in the seat headrests of real vehicles. Head protection was evaluated by dynamic loading in sled testing, in which the force on the head of the crash test dummy was measured. The head injury criterion improved from 274 to 155, indicating the superior performance of the tested structures compared to that achieved by energy absorption structures based on steel plates. Moreover, the deformation of auxetic structures prevented neck bending by holding the head. These findings present new possibilities for effectively protecting the human body by mitigating impact, facilitating energy absorption, and ensuring head stability.
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spelling doaj.art-a9815f13d54149b8abd1ebc8e34e2f3a2023-07-30T11:15:38ZengNature PortfolioScientific Reports2045-23222023-07-0113111210.1038/s41598-023-39200-8Transition of deformation modes from bending to auxetic compression in origami-based metamaterials for head protection from impactSunao Tomita0Kento Shimanuki1Shin Oyama2Hidekazu Nishigaki3Toshiaki Nakagawa4Masakazu Tsutsui5Youhei Emura6Masahiko Chino7Hirokazu Tanaka8Yoshinobu Itou9Kazuhiko Umemoto10Toyota Central R&D Labs., Inc.Toyota Central R&D Labs., Inc.Toyota Central R&D Labs., Inc.Toyota Central R&D Labs., Inc.Toyota Central R&D Labs., Inc.Vehicle Structure & Performance Development Division, TOYOTA AUTO BODY CO.,LTD.Vehicle Structure & Performance Development Division, TOYOTA AUTO BODY CO.,LTD.Vehicle Structure & Performance Development Division, TOYOTA AUTO BODY CO.,LTD.Vehicle Structure & Performance Development Division, TOYOTA AUTO BODY CO.,LTD.Vehicle Architecture Engineering Division, TOYOTA AUTO BODY CO., LTD.Toyota Central R&D Labs., Inc.Abstract For the protection of the human head by energy absorption structures, a soft mechanical response upon contact with the head is required to mitigate the effect of impact, while a hard mechanical response for highly efficient energy absorption is required to stop the movement of the head. This study realized the opposite mechanical properties during head protection by transitioning the deformation mode from bending to auxetic compression. First, non-linear finite element (FE) models were constructed to numerically reproduce the bending behavior. The calculated force responses agreed well with forces in bending tests. Using the FE models, the EA structures with proper transition of deformation modes were designed and installed in the seat headrests of real vehicles. Head protection was evaluated by dynamic loading in sled testing, in which the force on the head of the crash test dummy was measured. The head injury criterion improved from 274 to 155, indicating the superior performance of the tested structures compared to that achieved by energy absorption structures based on steel plates. Moreover, the deformation of auxetic structures prevented neck bending by holding the head. These findings present new possibilities for effectively protecting the human body by mitigating impact, facilitating energy absorption, and ensuring head stability.https://doi.org/10.1038/s41598-023-39200-8
spellingShingle Sunao Tomita
Kento Shimanuki
Shin Oyama
Hidekazu Nishigaki
Toshiaki Nakagawa
Masakazu Tsutsui
Youhei Emura
Masahiko Chino
Hirokazu Tanaka
Yoshinobu Itou
Kazuhiko Umemoto
Transition of deformation modes from bending to auxetic compression in origami-based metamaterials for head protection from impact
Scientific Reports
title Transition of deformation modes from bending to auxetic compression in origami-based metamaterials for head protection from impact
title_full Transition of deformation modes from bending to auxetic compression in origami-based metamaterials for head protection from impact
title_fullStr Transition of deformation modes from bending to auxetic compression in origami-based metamaterials for head protection from impact
title_full_unstemmed Transition of deformation modes from bending to auxetic compression in origami-based metamaterials for head protection from impact
title_short Transition of deformation modes from bending to auxetic compression in origami-based metamaterials for head protection from impact
title_sort transition of deformation modes from bending to auxetic compression in origami based metamaterials for head protection from impact
url https://doi.org/10.1038/s41598-023-39200-8
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