A numerical framework for hydroelastic analysis of a flexible floating structure under unsteady external excitations: Motion and internal force/moment

An effective numerical framework is constructed in which the discrete-module-beam hydroelasticity method is applied for analyzing the motion and internal force/moment of a flexible floating structure under unsteady external excitations. Procedures for dealing with three kinds of unsteady excitation forces are presented, namely a concentrated force only, a local continuously-distributed force and a combination of waves and unsteady local external loads. The strategy for obtaining hydroelastic responses of any given location of a VLFS is given, especially a hybrid integration-interpolation (HII) method is developed to calculate the VLFS's structural force response. Several loading processes are investigated. The calculated vertical displacements show a rather good agreement with the experimental data or the numerical results from other scholars, which validates the proposed framework. The bending moment distribution curve given by the HII method is compared with that given by the third-order interpolation scheme. The HII method is able to give the real structural force distribution curve at the initial stage of the loading process and shows an abrupt change on the location where a concentrated force is exerted.