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Final Comments

There is one final point to make about the nodal coordinates for the initial position of the sample pipeline model. Obviously the configuration in the plot represents a position in which the pipe restoring forces or stresses are in equilibrium with the applied loading and boundary conditions. The likelihood is that in general the coordinates which give this exact equilibrium position will not be known. It is probably possible to make a reasonable guess or approximation to the actual equilibrium position, but that is all it is – an approximation.

In fact, whenever you perform an analysis in which the initial position is not undeformed or stress free, Flexcom assumes the nodal coordinates specified are approximate. In such an analysis Flexcom begins by finding the exact equilibrium position and the corresponding initial stresses. The approximate nodal coordinates do not even have to be very close to the actual equilibrium position. The closer they are, the fewer iterations that will be required to find the exact equilibrium position, but this rate of convergence is the only thing that is affected by the nodal coordinates input.