Cable Analysis using Orthogonal Collocation

The capability to analyze and design cable systems during the deployment and retrieval phase must encompass the dynamic effects of paying out and reeling in the cable system. Past cable payout/reel in work has been preponderantly treated in a quasidynamic manner (4). With this quasidynamic approach, a dynamic analysis was performed at a fixed length, for several lengths of cable. More recently, spatially-discrete methods, such as the lumped parameter and finite element methods, have been employed in a manner where the length of the cable system is changed at each time integration step (11). These adjustments present a rather adrupt change in configuration and as a result, numerical oscillations can be introduced. Alternatively, cable systems undergoing changing length can be treated in a continuous fashion where full dynamic effects due to payout or reel in are considered (5).