In cable deployment processes involving laying lightweight segments on the ocean bottom, regions of the cable often have low-tension conditions, e.g. at touchdown of reverse curvature points. Traditional cable models in which load-adaptive equilibrium is maintained with only tensile forces are inadequate to simulate such problems. Recently developed elastica models which include flexural stiffness can simulate such problems but at the considerable extra cost of including several additional equations and variables at every integration point along the cable. A hybrid model and a solution scheme are presented herein to efficiently simulate low-tension oceanic cable deployment. The model consists of both a traditional flexible cable and an elastica with bending stiffness. The later is applied only to the local low-tension region near a point where the cable model would be ill-conditioned or singular. The hybrid two-point boundary value problem is solved by integrating two separate sets of governing equations from either end and by imposing continuity constraints at the conjunction point. A cable-laying example demonstrates the efficiency and efficacy of the method.
展开▼
