A nonlinear biphasic viscohyperelastic model for articular cartilage.
Experiments on articular cartilage have shown nonlinear stress-strain curves under finite deformations as well as intrinsic viscous effects of the solid phase. The aim of this study was to propose a nonlinear biphasic viscohyperelastic model that combines the intrinsic viscous effects of the proteoglycan matrix with a nonlinear hyperelastic constitutive equation. The proposed equation satisfies objectivity and reduces for uniaxial loading to a solid type viscous model in which the actions of the springs are represented by the hyperelastic function proposed by Holmes and Mow [1990. J. Biomechanics 23, 1145-1156.]. Results of the model, that were efficiently implemented in an updated Lagrangian algorithm, were compared with experimental infinitesimal data reported by DiSilverstro and Suh [2001. J. Biomechanics 34, 519-525.] and showed acceptable fitting for the axial force (R(2)=0.991) and lateral displacement (R(2)=0.914) curves in unconfined compression as well as a good fitting of the axial indentation force curve (R(2)=0.982). In addition, the model showed an excellent fitting of finite-deformation confined compression stress relaxation data reported by Ateshian et al. [1997. J. Biomechanics 30, 1157-1164.] and Huang et al. [2005. J. Biomechanics 38, 799-809.] (R(2)=0.993 and R(2)=0.995, respectively). The constitutive equation may be used to represent the mechanical behavior of the proteoglycan matrix in a fiber reinforced model of articular cartilage.
García
José Jaime
JJ
Escuela de Ingeniería Civil y Geomática, Universidad del Valle, Calle 13 # 100-00, Edif.. 350, of. 2012, A.A. 25360, Cali, Colombia. josejgar@univalle.edu.co
Cortés
Daniel Humberto
DH
D000818:Animals; D002358:Cartilage, Articular / Q000502:physiology*; D019245:Compressive Strength / Q000502:physiology; D003198:Computer Simulation; D005109:Extracellular Matrix / Q000502:physiology*; D020342:Finite Element Analysis; D006801:Humans; D008954:Models, Biological; D017711:Nonlinear Dynamics; D011509:Proteoglycans / Q000502:physiology*; D014783:Viscosity
D011509:Proteoglycans