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A nonlinear finite element formulation for axisymmetric torsion of biphasic materials. (English) Zbl 1012.74074

Summary: We present a finite element formulation for large-deformation torsional response of biphasic materials, with specific application to prediction of nonlinear coupling between torsional deformation and fluid pressurization in articular cartilage. Due to the use of a cylindrical coordinate system, a particular challenge arises in the linearization of the weak form. The torsional axisymmetric case considered gives rise to additional geometric terms, which are important for the robustness of numerical implementation and that would not be present in Cartesian formulation. A detailed derivation of this linearization process is given, couched in the context of a variational formulation suitable for finite element implementation. A series of numerical parametric studies are presented and compared to experimental measurements of time-dependent response of cartilage.

MSC:

74S05 Finite element methods applied to problems in solid mechanics
74L15 Biomechanical solid mechanics
92C10 Biomechanics
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