Global and structural hydroelastic analysis of a large container ship with forward speed using multi-module method

For large container ships, their low structure stiffness caused by large main particulars and openings bring hydroelastic problems. The forward speed alters hydrodynamics encounter frequency and amplitude, inducing difficulties in global and structural analysis. Additionally, the local deformations, which are crucial in stress analysis, are difficult to be predicted by modal superposition method. To address these problems, this paper adopts the speed-dependent beam-connected discrete-modules (BCDM) method for frequency-domain hydroelastic analysis. In this method, the container ship is discretized into several rigid modules connected by a hull girder. The double body flow model is used to obtain multi-body hydrodynamic with speed effect, while the thin-walled beam model is used to derive hull girder stiffness. By coupling the multi-body hydrodynamic with hull girder stiffness, the hydroelastic equation is established. Finally, the pressure and inertial loads from each module are statically mapped onto the finite element model for stress analysis, including global and local deformations. The analysis process is applied to a 14,000 TEU container ship. The global response results are validated through a segmented ship model experiment. Furthermore, the effects of flexibility and speed are analyzed. The results indicate that, at service speed, the hydroelastic response of the sectional loads can be up to four times larger than quasi-static result. Local deformations contribute to increased stress at locations such as the bottom plate between transverse bulkheads and the hatch corners.The analysis method may provide an effective approach for integrated hydroelastic analysis and structural safety verification of large vessels in engineering application. • Hydroelastic response of navigating containership is analyzed by multi-module method. • Ship motion and sectional loads results are validated by segmented model experiment. • Hydroelastic response of sectional loads is up to 4 times of the quasi-static result. • Local deformations can increase stress by up to 20 percent.