TY - JOUR
T1 - Structural elasticity for tensile deformation of a single human hair and the comparison with it for the bending deformation
AU - Tohmyoh, Hironori
AU - Fujita, Kento
AU - Suzuki, Hitoshi
AU - Futada, Kei
N1 - Funding Information:
The authors would like to acknowledge Professor J. Cui at Xi'an Jiaotong University, who has stayed at Tohoku University as a JSPS postdoctoral fellow, for his valuable discussions on this work. This work was supported by JSPS KAKENHI Grant Number 18H01331.
Funding Information:
The authors would like to acknowledge Professor J. Cui at Xi'an Jiaotong University, who has stayed at Tohoku University as a JSPS postdoctoral fellow, for his valuable discussions on this work. This work was supported by JSPS KAKENHI Grant Number 18H01331 .
Publisher Copyright:
© 2020 Elsevier Ltd
PY - 2021/1
Y1 - 2021/1
N2 - Human hair is a multi-layered structure, which consists of the inner medulla, middle cortex, and outer cuticle. Therefore, the mechanical properties of the hair are related not only to the Young's modulus of each layer but also to the internal structures. Although the tensile test of a human hair has been performed elsewhere, the deformability of the hair for the tensile deformation is determined as the Young's modulus of the hair structure, which is similar to that of metals. In this paper, the structural elasticity of a single human hair for the tensile deformation, which expresses the deformability of a hair by tension without being dependent on external dimensions and shape, is defined based on the theoretical model, and is measured by performing the tensile test under the digital microscope observation. The values of the structural elasticity for the tensile deformation of the hair samples collected from healthy persons are compared with the values obtained for bending deformation. The structural elasticity for the tensile deformation of the hair sample is found to be lesser than that of the bending deformation, and this is verified to be always valid provided the Young's modulus of the outer cuticle is greater than that of the middle cortex.
AB - Human hair is a multi-layered structure, which consists of the inner medulla, middle cortex, and outer cuticle. Therefore, the mechanical properties of the hair are related not only to the Young's modulus of each layer but also to the internal structures. Although the tensile test of a human hair has been performed elsewhere, the deformability of the hair for the tensile deformation is determined as the Young's modulus of the hair structure, which is similar to that of metals. In this paper, the structural elasticity of a single human hair for the tensile deformation, which expresses the deformability of a hair by tension without being dependent on external dimensions and shape, is defined based on the theoretical model, and is measured by performing the tensile test under the digital microscope observation. The values of the structural elasticity for the tensile deformation of the hair samples collected from healthy persons are compared with the values obtained for bending deformation. The structural elasticity for the tensile deformation of the hair sample is found to be lesser than that of the bending deformation, and this is verified to be always valid provided the Young's modulus of the outer cuticle is greater than that of the middle cortex.
KW - Bending deformation
KW - Cuticle
KW - Human hair
KW - Internal structure
KW - Structural elasticity
KW - Tensile deformation
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U2 - 10.1016/j.jmbbm.2020.104166
DO - 10.1016/j.jmbbm.2020.104166
M3 - Article
C2 - 33129035
AN - SCOPUS:85094318703
SN - 1751-6161
VL - 113
JO - Journal of the Mechanical Behavior of Biomedical Materials
JF - Journal of the Mechanical Behavior of Biomedical Materials
M1 - 104166
ER -
