title: Investigations on the viscoelastic behaviour of a human healthy heel pad: in vivo compression tests and numerical analysis.
abstract: The aim of this study was to investigate the viscoelastic behaviour of the human heel pad by comparing the stress-relaxation curves obtained from a compression device used on an in vivo heel pad with those obtained from a three-dimensional computer-based subject-specific heel pad model subjected to external compression. The three-dimensional model was based on the anatomy revealed by magnetic resonance imaging of a 31-year-old healthy female. The calcaneal fat pad tissue was described with a viscohyperelastic model, while a fibre-reinforced hyperelastic model was formulated for the skin. All numerical analyses were performed to interpret the mechanical response of heel tissues, with loading conditions and displacement rate in agreement with experimental tests. The heel tissues showed a non-linear, viscoelastic behaviour described by characteristic hysteretic curves, stress-relaxation and viscous recovery phenomena. The reliability of the investigations was validated by the interpretation of the mechanical response of heel tissues under the application of three pistons with diameter of 15, 20 and 40 mm, at the same displacement rate of about 1.7 mm/s. The maximum and minimum relative errors were found to be less than 0.95 and 0.064, respectively.
authors: Department of Mechanics and Industrial Technologies, University of Florence, via di S. Marta 3, 50139 Florence, Italy. sara.matteoli@unifi.it
authors: Sara
authors: S
authors: Matteoli
authors: Chiara G
authors: CG
authors: Fontanella
authors: Emanuele L
authors: EL
authors: Carniel
authors: Jens E
authors: JE
authors: Wilhjelm
authors: Antonio
authors: A
authors: Virga
authors: Nadège
authors: N
authors: Corbinz
authors: Andrea
authors: A
authors: Corvi
authors: Arturo N
authors: AN
authors: Natali
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D004548:Elasticity; D005260:Female; D057918:Fiducial Markers; D006365:Heel / Q000033:anatomy & histology* / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D011312:Pressure; D015203:Reproducibility of Results; D013314:Stress, Mechanical; D014783:Viscosity