Release Time:2019-03-09  Hits:

Indexed by: Journal Article

Date of Publication: 2014-01-01

Journal: SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY

Included Journals: EI、SCIE

Volume: 57

Issue: 1

Page Number: 152-165

ISSN: 1674-7348

Key Words: coupled method; full time-domain; second-order; truss spar; rod theory; irregular wave

Abstract: A new full time-domain nonlinear coupled method has been established and then applied to predict the responses of a Truss Spar in irregular wave. For the coupled analysis, a second-order time-domain approach is developed to calculate the wave forces, and a finite element model based on rod theory is established in three dimensions in a global coordinate system. In numerical implementation, the higher-order boundary element method (HOBEM) is employed to solve the velocity potential, and the 4th-order Adams-Bashforth-Moultn scheme is used to update the second-order wave surface. In deriving convergent solutions, the hull displacements and mooring tensions are kept consistent at the fairlead and the motion equations of platform and mooring-lines/risers are solved simultaneously using Newmark-beta integration scheme including Newton-Raphson iteration. Both the coupled quasi-static analysis and the coupled dynamic analysis are performed. The numerical simulation results are also compared with the model test results, and they coincide very well as a whole. The slow-drift responses can be clearly observed in the time histories of displacements and mooring tensions. Some important characteristics of the coupled responses are concluded.