Dynamic responses of serially connected truss pontoon-MOB – A numerical investigation

Abstract

Very large floating structures (VLFS) are typically made up of several modules of offshore platforms, such as semi-submersibles, connected by mechanical connectors. The proposed Truss Pontoon Mobile Offshore Base (TP-MOB) is a new type of offshore platform based on the truss pontoon semi-submersible design. The design of the connectors is crucial for the functionality of the structure. In this study, the flexible connectors are modeled with a 3D source distribution method and the wave forces are estimated with 3D linear potential theory. The open-source finite element-based numerical model, HYDRAN-XR, is used to analyze the structural responses and connector forces in both regular and irregular wave conditions. The results indicate significant differences in responses between single and multi-module cases, especially in extreme waves. Loads on the connector change greatly for three- and five-module cases, with maximum values at specific wave angles.