Eigenvalue Analysis for Motion Response of a TLP and Tender Semi Considering a Complex Mooring Configuration

Abstract

Eigenvalue analysis was carried out for a complex system of multiple floating bodies with various connectors. In this study, multiple floating bodies are a tension leg platform (TLP) and a semisubmersible platform that are connected with hawser and mooring lines. To perform the eigenvalue analysis, mathematical formulation is derived including linear stiffness and added mass matrices. A systematic approach is adopted for the derivation of the linear stiffness matrix by considering both pretension and spring effects, which can be applied to general floating body system with complex moorings. First, a single floating body system of the TLP is investigated to validate the present eigenvalue analysis method. Discussion is made on the effect of mooring pretension or axial stiffness on the natural period of the floating body. Then, a multiple floating body system including the TLP and tender semi is considered. In this case, the analysis results are validated by comparison with the experimental data.