Main analysis methods
There is a range of analysis methods that, seen from a bird's view, increasingly refine the analysis process, especially the behaviour of the pipeline.
•The 'standard method' is the linear elastic analysis method. The external loadings are in equilibrium in the undeformed state of the structure.
•In case of large displacements, especially rotations, or if the interaction between axial forces and lateral displacements become significant, the geometric non-linear method is advised. The external loadings are in equilibrium in the deformed state of the structure.
•In case of a thin-walled pipeline the non-linear stiffness behaviour of bends en straight pipes becomes important. Increasing ovalisation of the cross section due to bending, influences the bend bending stiffness of the pipe.
•If the magnitude of the ovalisation of the cross-section is unacceptable, in certain circumstances the soil ring stiffening option (flexible cross-section) may be applied resulting in a reduced ovalisation in most cases.
•If the material of the pipe starts yielding, the deformations increase in such a way that equilibrium between internal forces and external loadings remains, until the point is reached where the structure fails.
AnalysisMethods, last changed: 11/4/2020