Coupled analysis between mooring system and VLFS with an effect of elastic deflection of floater. (1st October 2018)

• Record Type: Journal Article
• Authors: Ni, Xinyun; Cheng, Xiaoming; Wu, Bo; Wang, Xuefeng
• Is Part Of: Ocean engineering. Volume 165(2018)
• Page Start: 319
• Page End: 327
• Publication Date: 2018-10-01
• Subjects: Mooring tension -- Hydroelasticity -- Elastic deflection -- Static analysis; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2018.07.044
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: The conventional mooring analysis considers the motion of the floater as a rigid body. However, as the dimension of the floater increases, the elastic deflection of the floater may become significant which can have an impact on mooring tensions. In this paper, based on the three dimensional hydroelasticity and quasi-static mooring analysis method, a coupled numerical analysis method for a Very Large Floating Structure (VLFS) and mooring system is established. The elastic deflection amplitudes and phases of various modes of a VLFS are first computed in regular waves in frequency domain, these are then converted into time series for the specified real sea state, and time domain simulations for the vessel's motion and mooring tension are performed. In the time domain simulation, the displacements at mooring connection points on the vessel include both the rigid motion and elastic deflection of the vessel. A single VLFS module was analyzed together with a mooring system to demonstrate the procedure of the analysis. Furthermore a VLFS consists of three modules with a mooring system was also analyzed. The calculation results match well with the data from model test, which indicates the validity of the numerical method proposed and the computing program developed. Highlights: Based on 3D hydroelastical theory, a coupled time domain method has been established to analyze the mooring tensions characters. The expression formula of the displacement at mooring point due to elastic deflection in time history has been built. Using the self-developed software, the mooring systems performance of a VLFS has been analyzed. The elastic deflection of the floater surely has influence on the mooring tensions as the floater dimension is large enough.