Skip to Main content Skip to Navigation
Theses

Caractérisation des propriétés mécaniques de la peau humaine in vivo via l'IRM

Abstract : The human skin is a complex biological material. It consists of three layers of different thicknesses: epidermis, dermis and hypodermis. This structural complexity gives the skin of the mechanical properties of complex hyperelastic, nonlinear, viscoelastic and submitted to the pre-tension. An indentation composed of 6 loading levels and running in the MRI environment has been developed. Indentation tests were performed on the dorsal part of the left forearm of 9 subjects of ages ranging from 26 to 40 years. For each subject, 28 MRI images were built. Each image represents a slice of the forearm. The images were then processed through a medical images processing software in house in order to reconstruct skin layers, muscles and bones. Finally, a finite element model in 2D was built from MRI images at the initial configuration (without load) using a pre-processor MSC.Patran 2005. This model consists of 4 layers of different materials: three skin layers and a muscle layer. The bones were supposed rigid and fixed. The Neo-Hooke hyperelastic incompressible constitutive law with one parameter to identify C10 was used for all 4 layers of materials (C10,Epi., C10,Der., C10,Hyp., C10,Mus.) . Indentation tests were simulated using a solver MSC.Marc 2005. The error between the simulation results and those of the experiment was measured by an objective function. The identification of parameters of the constitutive law was conducted by the minimization of the objective function via Levenberg-Marquardt algorithm developed under MatLab environment. The numerical validation of the identification process has shown that the minimum is only provided when the first two layers (epidermis and dermis) behave as a single layer (C10,E+D). The identification results provide a range of values for a population of 9 subjects: C10,E+D = [60-370] kPa; C10,Hyp. = [0,04-4] kPa; C10,Mus. = [0,7-1,7] kPa. The results reflect the human variability of mechanical properties.
Complete list of metadatas

Cited literature [97 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-00207740
Contributor : Chantal Guilbert <>
Submitted on : Friday, January 18, 2008 - 11:08:11 AM
Last modification on : Thursday, January 11, 2018 - 6:17:20 AM
Long-term archiving on: : Tuesday, April 13, 2010 - 11:09:18 PM

Identifiers

  • HAL Id : tel-00207740, version 1

Collections

Citation

H.V. Tran. Caractérisation des propriétés mécaniques de la peau humaine in vivo via l'IRM. Mécanique [physics.med-ph]. Université de Technologie de Compiègne, 2007. Français. ⟨tel-00207740⟩

Share

Metrics

Record views

1664

Files downloads

29189