Table 1.
FE model material properties
| Component | Material properties | Constitutive relation | Element type |
|---|---|---|---|
| Vertebral cortical bone27 |
E = 12 000 MPa υ = 0.3 |
Isotropic, elastic | 8 Nodes brick element (C3D8) |
| Vertebral cancellous bone27 |
E = 100 MPa υ = 0.2 |
Isotropic, elastic | 4 Nodes tetrahedral element (C3D4) |
| Pelvic cortical bone (Sacrum, Ilium)14 |
E = 17 000 MPa υ = 0.3 |
Isotropic, elastic | 4 Nodes tetrahedral element (C3D4) |
| Sacrum cancellous bone28 | Heterogeneous | Isotropic, elastic | 4 Nodes tetrahedral element (C3D4) |
| Ilium cancellous bone28 |
E = 70 MPa υ = 0.2 |
Isotropic, elastic | 4 Nodes tetrahedral element (C3D4) |
| Femur cortical bone22 |
E = 17 000 MPa υ = 0.29 |
Isotropic, elastic | 4 Nodes tetrahedral element (C3D4) |
| Femur cancellous bone22 |
E = 100 MPa υ = 0.2 |
Isotropic, elastic | 4 Nodes tetrahedral element (C3D4) |
| Ground substance of annulus fibrosis29 |
C 10 = 0.035 K 1 = 0.296 K 2 = 65 |
Hyperelastic anisotropic (HGO) | 8 Nodes brick element (C3D8) |
| Nucleus pulposus27 |
E = 1 MPa υ = 0.499 |
Isotropic, elastic | 8 Nodes brick element (C3D8) |
| Anterior longitudinal27 | 7.8 MPa (<12%), 20 MPa (>12%) | Non‐linear hypoelastic | Truss element (T3D2) |
| Posterior longitudinal27 | 10 MPa (<11%), 20 MPa (>11%) | Non‐linear hypoelastic | Truss element (T3D2) |
| Ligamentum flavum27 | 15 MPa (<6.2%), 19.5 MPa (>6.2%) | Non‐linear hypoelastic | Truss element (T3D2) |
| Intertransverse27 |
10 MPa (<18%), 58.7 MPa (>18%) |
Non‐linear hypoelastic | Truss element (T3D2) |
| Interspinous27 | 10 MPa (<14%), 11.6 MPa (>14%) | Non‐linear hypoelastic | Truss element (T3D2) |
| Supraspinous27 | 8 MPa (<20%), 15 MPa (>20%) | Non‐linear hypoelastic | Truss element (T3D2) |
| Capsular27 | 7.5 MPa (<25%), 32.9 MPa (>25%) | Non‐linear hypoelastic | Truss element (T3D2) |
| Anterior SIJ30 | 125 MPa (5%), 325 MPa (>10%), 316 MPa (>15%) | Non‐linear hypoelastic | Truss element (T3D2) |
| Short posterior SI30 | 43 MPa (5%), 113 MPa (>10%), 110 MPa (>15%) | Non‐linear hypoelastic | Truss element (T3D2) |
| Long posterior SI30 | 150 MPa (5%), 391 MPa (>10%), 381 MPa (>15%) | Non‐linear hypoelastic | Truss element (T3D2) |
| Intraosseus30 | 40 MPa (5%), 105 MPa (>10%), 102 MPa (>15%) | Non‐linear hypoelastic | Truss element (T3D2) |
| Sacrospinous30 | 304 MPa (5%), 792 MPa (>10%), 771 MPa (>15%) | Non‐linear hypoelastic | Truss element (T3D2) |
| Sacrotuberous30 | 326 MPa (5%), 848 MPa (>10%), 826 MPa (>15%) | Non‐linear hypoelastic | Truss element (T3D2) |
| Gluteus maximus31 | k = 344 N/mm | — | Connector element |
| Gluteus medius31 | k = 779 N/mm | — | Connector element |
| Gluteus minimus31 | k = 660 N/mm | — | Connector element |
| Psoas major31 | k = 100 N/mm | — | Connector element |
| Adductor magnus31 | k = 257 N/mm | — | Connector element |
| Adductor longus31 | k = 134 N/mm | — | Connector element |
| Adductor brevis31 | k = 499 N/mm | — | Connector element |