STOCHASTIC NONLINEAR RESPONSE OF COUPLED TENDON-RIGID BODY SYSTEM

A coupled tendon-rigid body model which may be used for the study of offshore or space structures is presented. A set of fully non-linear equations of motion for a single-tendon tension leg platform are developed. The response is analyzed for random wave and steady current loading. Motion is assumed to be planar and the equations of motion for the elastic tendon and the rigid hull are coupled. The response is determined numerically in the time domain by implementing a finite difference scheme. The responses for a model with a 470 m long tendon and a 50 m long hull exhibit both transient and steady state behavior. When waves forces alone are applied, the system oscillates about its vertical position. A combined load of waves and current produce an oscillation about an offset position, as has been shown in the literature. The analytical model presented in this paper would be useful to the designers of TLPs in determining the overall dynamic response characteristics.

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