Table 2.
A set of material parameters for finite element simulation with fibril-reinforced poroviscoelastic swelling model
| Material parameters | Input value | References | |
|---|---|---|---|
| Nucleus | Annulus | ||
| Young’s modulus | 0.15 MPa | 1.5 MPa | [2, 19] |
| Extrafibrillar fluid fraction | 70% | 60% | [27, 41] |
| Fixed charge density | 0.24 mEq/ml | 0.18 mEq/ml | [19, 27] |
| Viscoelastic properties of collagen fibers | – |
E0 = 3.337 MPa, Eε = 380.8 MPa η = 1,532.39 MPas |
[38] |
| Poisson ratio | 0.17 | [28, 42, 43] | |
| Hydraulic permeability | 5.0 × 10−16 m4N−1s−1 | [2, 19, 43, 44] | |
Because the model is poroviscoelastic, Poisson’s ratio in the table relates to the porous solid, not to the solid filled with fluid. Therefore, Poisson’s ratio is very different from its incompressibility value of 0.5 [28]