Dynamic modeling of cables for underwater applications

Abstract

Dynamic modeling of cables is a research theme of great importance and practical application nowadays. However, due to non-linearity behavior present on cable dynamics, as well as the need to work with many degrees of freedom, to develop dynamic models for these systems becomes a hard task. To develop dynamic models of cables, this article uses the Lumped Mass Approach Method, which supposes the cable divided in rigid links connected by fictitious elastic joints. The cables were considered with one of its endings articulated to a floating structure (ship or platform), while on the other ending were considered two cases: one free terminal loading; ending fixed to the ground. The cables are submersed and the hydrodynamic drag was considered from a simple model, proportional to the velocity’s square. Using the Euler-Lagrange Formalism, the dynamic models for cables considering two, three and four links were developed. Once these models were obtained, simulations were performed, proving the results agreeing qualitatively with the physical expected.