ABSTRACT:

The present paper gives an overall description of a computerized method which analyzes in the time domain the three - dimensional dynamic behavior of ocean cablebody systems. A lumped parameter approach is" used to model the cable- body system. The program calculates the dynamic tension and motion responses· Current profiles, in -line packages, ship speed, water surface and seafloor boundaries, payload propulsion can be simulated. The model is capable of analysing both constant diameter and lumpy arrays of arbitrary buoyancies. The highly nonlinear equations of motion are decoupled for the unknowns and solved numerically with respect to an earth fixed inertial reference frame by a forth - order Rung - Kutta method. The first example basically check the accuracy of the formulation for two dimensional cases. Another example involving circular turn maneuvers of the lower end vehicle, the calculated results show the effects that current affects the configuration and tension.

INTRODUCTION

Many ocean cable systems are configured with a series of cables connecting discrete packages. Such a configuration is common due to its ease and simplicity of design, fabrication. Examples include vertical lift systems often used in deployment and recovery of objects, catenary mooring systems for surface ships and barges; cable systems with a tethered powered vehicle at one end; towed cable systems; and suspended cable sensor systems. If cross- currents are considered, the cable body system should be considered as a three - dimensional problem. Currently, there exist various types of methods for analyzing unsteady motions of cable - body systems. Main difference between these methods lies in the way the cable is treated[l- 2].It was found that when the system was assumed to e composed of an interconnected set of simple elements, many of the limitations of the semi - analytical methods could be avoided.

This content is only available via PDF.
You can access this article if you purchase or spend a download.