Strain-rate dependence of viscous properties of the plantar soft tissue identified by a spherical indentation test

Takuo Negishi, Kohta Ito, Arinori Kamono, Taeyong Lee, Naomichi Ogihara

Research output: Contribution to journalArticle

Abstract

The mechanical properties of the plantar soft tissue are known to vary in diabetic patients, indicating that parameter identification of the mechanical properties of the foot tissue using an indentation test is clinically important for possible early diagnosis and interventions of diabetic foot. However, accurate mechanical characterization of the viscous properties of the plantar soft tissue has been difficult, as measured force-relaxation curves of the same soft tissue differ depending on how the material is loaded. In the present study, we attempted to clarify how the indentation rate of the plantar soft tissue affects the measured force-relaxation curves, which is necessary in order to identify the viscoelastic properties. The force-relaxation curves of the heel pads were obtained from the indentation experiment in vivo at indentation rates of 15, 25, 50, 75, and 100 mm/s. The curves were fit to an analytical contact model of spherical indentation incorporating a five-element Maxwell model. The results of the present study demonstrated that, although experimentally obtained force-relaxation curves were actually variable depending on the indentation rate, similar viscous parameters could be identified for the same heel if the effects of (1) the underestimation of the peak force due to the energy dissipation occurring during indentation and (2) the deceleration of the indenter at the target position were incorporated in the parameter identification process. The indentation-rate-independent viscous properties could therefore be estimated using the proposed method.

Original languageEnglish
Article number103470
JournalJournal of the Mechanical Behavior of Biomedical Materials
Volume102
DOIs
Publication statusPublished - 2020 Feb

Fingerprint

Indentation
Strain rate
Tissue
Identification (control systems)
Mechanical properties
Deceleration
Energy dissipation

Keywords

  • Damping
  • Foot
  • Heel pad
  • Plantar soft tissue

ASJC Scopus subject areas

  • Biomaterials
  • Biomedical Engineering
  • Mechanics of Materials

Cite this

Strain-rate dependence of viscous properties of the plantar soft tissue identified by a spherical indentation test. / Negishi, Takuo; Ito, Kohta; Kamono, Arinori; Lee, Taeyong; Ogihara, Naomichi.

In: Journal of the Mechanical Behavior of Biomedical Materials, Vol. 102, 103470, 02.2020.

Research output: Contribution to journalArticle

@article{32ea2283bd3f4ec4bb892cc20bbdac11,
title = "Strain-rate dependence of viscous properties of the plantar soft tissue identified by a spherical indentation test",
abstract = "The mechanical properties of the plantar soft tissue are known to vary in diabetic patients, indicating that parameter identification of the mechanical properties of the foot tissue using an indentation test is clinically important for possible early diagnosis and interventions of diabetic foot. However, accurate mechanical characterization of the viscous properties of the plantar soft tissue has been difficult, as measured force-relaxation curves of the same soft tissue differ depending on how the material is loaded. In the present study, we attempted to clarify how the indentation rate of the plantar soft tissue affects the measured force-relaxation curves, which is necessary in order to identify the viscoelastic properties. The force-relaxation curves of the heel pads were obtained from the indentation experiment in vivo at indentation rates of 15, 25, 50, 75, and 100 mm/s. The curves were fit to an analytical contact model of spherical indentation incorporating a five-element Maxwell model. The results of the present study demonstrated that, although experimentally obtained force-relaxation curves were actually variable depending on the indentation rate, similar viscous parameters could be identified for the same heel if the effects of (1) the underestimation of the peak force due to the energy dissipation occurring during indentation and (2) the deceleration of the indenter at the target position were incorporated in the parameter identification process. The indentation-rate-independent viscous properties could therefore be estimated using the proposed method.",
keywords = "Damping, Foot, Heel pad, Plantar soft tissue",
author = "Takuo Negishi and Kohta Ito and Arinori Kamono and Taeyong Lee and Naomichi Ogihara",
year = "2020",
month = "2",
doi = "10.1016/j.jmbbm.2019.103470",
language = "English",
volume = "102",
journal = "Journal of the Mechanical Behavior of Biomedical Materials",
issn = "1751-6161",
publisher = "Elsevier BV",

}

TY - JOUR

T1 - Strain-rate dependence of viscous properties of the plantar soft tissue identified by a spherical indentation test

AU - Negishi, Takuo

AU - Ito, Kohta

AU - Kamono, Arinori

AU - Lee, Taeyong

AU - Ogihara, Naomichi

PY - 2020/2

Y1 - 2020/2

N2 - The mechanical properties of the plantar soft tissue are known to vary in diabetic patients, indicating that parameter identification of the mechanical properties of the foot tissue using an indentation test is clinically important for possible early diagnosis and interventions of diabetic foot. However, accurate mechanical characterization of the viscous properties of the plantar soft tissue has been difficult, as measured force-relaxation curves of the same soft tissue differ depending on how the material is loaded. In the present study, we attempted to clarify how the indentation rate of the plantar soft tissue affects the measured force-relaxation curves, which is necessary in order to identify the viscoelastic properties. The force-relaxation curves of the heel pads were obtained from the indentation experiment in vivo at indentation rates of 15, 25, 50, 75, and 100 mm/s. The curves were fit to an analytical contact model of spherical indentation incorporating a five-element Maxwell model. The results of the present study demonstrated that, although experimentally obtained force-relaxation curves were actually variable depending on the indentation rate, similar viscous parameters could be identified for the same heel if the effects of (1) the underestimation of the peak force due to the energy dissipation occurring during indentation and (2) the deceleration of the indenter at the target position were incorporated in the parameter identification process. The indentation-rate-independent viscous properties could therefore be estimated using the proposed method.

AB - The mechanical properties of the plantar soft tissue are known to vary in diabetic patients, indicating that parameter identification of the mechanical properties of the foot tissue using an indentation test is clinically important for possible early diagnosis and interventions of diabetic foot. However, accurate mechanical characterization of the viscous properties of the plantar soft tissue has been difficult, as measured force-relaxation curves of the same soft tissue differ depending on how the material is loaded. In the present study, we attempted to clarify how the indentation rate of the plantar soft tissue affects the measured force-relaxation curves, which is necessary in order to identify the viscoelastic properties. The force-relaxation curves of the heel pads were obtained from the indentation experiment in vivo at indentation rates of 15, 25, 50, 75, and 100 mm/s. The curves were fit to an analytical contact model of spherical indentation incorporating a five-element Maxwell model. The results of the present study demonstrated that, although experimentally obtained force-relaxation curves were actually variable depending on the indentation rate, similar viscous parameters could be identified for the same heel if the effects of (1) the underestimation of the peak force due to the energy dissipation occurring during indentation and (2) the deceleration of the indenter at the target position were incorporated in the parameter identification process. The indentation-rate-independent viscous properties could therefore be estimated using the proposed method.

KW - Damping

KW - Foot

KW - Heel pad

KW - Plantar soft tissue

UR - http://www.scopus.com/inward/record.url?scp=85072929450&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85072929450&partnerID=8YFLogxK

U2 - 10.1016/j.jmbbm.2019.103470

DO - 10.1016/j.jmbbm.2019.103470

M3 - Article

C2 - 31605932

AN - SCOPUS:85072929450

VL - 102

JO - Journal of the Mechanical Behavior of Biomedical Materials

JF - Journal of the Mechanical Behavior of Biomedical Materials

SN - 1751-6161

M1 - 103470

ER -