Annulus fibrosus microstructure: an explanation to local heterogeneities

Adrien Baldit (1, 2, 3) , Dominique Ambard (2, 3) , Fabien Cherblanc (2, 3) , Pascale Royer (2, 3)

1 Department of Mechanical Engineering [Sheffield]
2 LMGC - Laboratoire de Mécanique et Génie Civil
3 BIOTIC - Biomécanique des Interactions et de l'Organisation des Tissus et des Cellules

Annulus fibrosus (AF) is the outer tissue of intervertebral discs (IVD). Its peculiar microstructure and biphasic composition define by an oriented fibre network embedded in a highly hydrated matrix (60−70%) is usually assimilated to porous composite material. It confers to AF a nonlinear, viscous and anisotropic behaviour. Many experimental and numerical studies underlined the anisotropic and non-linear mechanical behaviours on averaged values [Ambard and Cherblanc, 2009; Malandrino et al, 2011] but fail to represent the experimental strain heterogeneities [Baldit et al, 2013a; Michalek et al, 2010], that would be related to the microstructure and the biphasic constitution. On the other hand, characterization rarely relies on volumic behavior but it’s relevant when models deal with soft porous media [Baldit et al, 2013b]. This work aims to couple a poro-hyper-elastic model identification with homogenized and discretized geometries highlighting model sensitivity and limits regarding experimental transverse strains measurements.

Mots clés: Annulus Fibrosus; Intervertebral Disc; Hydro-Chemo-Mechanical Model; Finite Element; Digital Image Correlation

Domaines: Biomécanique [physics.med-ph]; Mécanique des matériaux [physics.class-ph]; Mécanique [physics.med-ph]

Adrien Baldit, Dominique Ambard, Fabien Cherblanc, Pascale Royer. Annulus fibrosus microstructure: an explanation to local heterogeneities. 39ème congrès de la Société de Biomécanique, Aug 2014, Valenciennes, France. ⟨10.1080/10255842.2014.931092⟩. ⟨hal-01219449⟩