Table 1.
Material properties and element type of bony structures, ligaments, intervertebral disk, and facet joint (Agarwal et al., 2013a,b).
| Material | Element type | Constitutive relation | Material properties |
|---|---|---|---|
| Bony structures | |||
| Vertebral cortical bone, endplates, and posterior cortical bone | 8 Nodes brick element (C3D8) | Isotropic, elastic | E = 12,000 MPa ν = 0.3 |
| Vertebral cancellous bone and posterior cancellous bone | 8 Nodes brick element (C3D8) | Isotropic, elastic | E = 100 MPa ν = 0.2 |
| Ligaments | Elastic modulus MPa (strain %) | ||
| Anterior longitudinal | Tension-only, truss elements (T3D2) | Hypoelastic | 7.8 (<12%), 20.0 (>12%) ν = 0.3 |
| Posterior longitudinal | Tension-only, truss elements (T3D2) | Hypoelastic | 10.0 (<11%), 20.0 (>11%) ν = 0.3 |
| Ligamentum flavum | Tension-only, truss elements (T3D2) | Hypoelastic | 15.0 (<6.2%), 19.5 (>6.2%) ν = 0.3 |
| Intertransverse | Tension-only, truss elements (T3D2) | Hypoelastic | 10.0 (<18%), 58.7 (>18%) ν = 0.3 |
| Interspinous | Tension-only, truss elements (T3D2) | Hypoelastic | 10.0 (<14%), 11.6 (>14%) ν = 0.3 |
| Supraspinous | Tension-only, truss elements (T3D2) | Hypoelastic | 8.0 (<20%), 15.0 (>20%) ν = 0.3 |
| Capsular | Tension-only, truss elements (T3D2) | Hypoelastic | 7.5 (<25%), 32.9 (>25%) ν = 0.3 |
| Intervertebral disk | |||
| Nucleus pulposus | 8 Nodes brick element (C3D8) | Isotropic, elastic | E = 2 MPa ν = 0.499 |
| Annulus fibrosus | 8 Nodes brick element (C3D8) | Hyperelastic anisotropic (HGO) | Table 2 |
| Apophyseal joints | GAPUNI elements | Non-linear soft contact | Pressure overclosure = 12,000 MPa |