Numerical analysis of pipeline dynamics in seabed laying

The paper analyses a mathematical model of the pipelaying from the stinger onto the seabed. The model is three-dimensional, nonlinear, it takes into account the interaction between the pipeline (PL) and the seabed, at the contact zone of PL and the stinger at discreet points. To solve equations, a numerical method is proposed which enables them to overcome some difficulties associated with the presence of substantial nonlinearities in the equations, the changes of PL section lengths in time which span in the sea and are lay on the seabed and the stinger, as well as with the indefinite selection of the stinger contact rollers. The paper finds some mechanisms in the contact rollers location along the stinger. Some examples are provided concerning the proper selection of the stinger and of PL parameters in laying PL at a depth of 320 m; it also gives an example of calculation of PL oscillations during the oscillating motions of the vessel.