Research Article
Efficient Fatigue Analysis of Helix Elements in Umbilicals and Flexible Risers: Theory and Applications
Table 1
Typical elements used in modeling and analysis of axis-symmetrical response.
| Element type | Assumption |
|
Thin cylindrical element | Constant through thickness radial displacements; axial, circumferential, and in-plane shear strains: , , and . |
Thick cylindrical element | Logarithmic through thickness radial displacements; radial, axial, circumferential, and in-plane shear strains: , , , and . |
Core element | Generalized cylinder element where the effect is expressed through and element stiffness matrix: . |
Helix element | Helix element with axial strains only: . | Helix element | Helix element with axial strains, curvatures, and torsional shear strains: , , , and . |
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