Abstract

This paper analyzes the partitioned and monolithic strategies to simulate tightly coupled hidroelastic problems. The seakeeping hydrodynamics solver used is based on a first-order linear time-domain FEM model with forward speed and double-body linearization. The structural dynamics solver is based on a full 3D time-domain FEM with corotational shell elements accounting for the geometric non-linearity. Both solvers are implemented under the same programming framework, which allows to implement the monolithic strategy, and to minimize the communication overheads of the partitioned strategy. Two case studies are used to test and compare the partitioned and monolithic coupling: a flexible catamaran in oblique waves, and a large floating reticulated structure made of fiber reinforced plastic. In both cases, the monolithic strategy is between three and four times faster than the partitioned strategy. This project has been developed under the H2020 project FIBRESHIP aimed at developing the technology to design and build the structure of large-length vessels in fiber reinforced polymers.

Abstract

In this paper, a simplified numerical approach is applied to the analysis of the linear vibrations of aluminum or composite marine propeller blades with embedded viscoelastic films, around a predeformed nonlinear state. This approach allows to evaluate in a sequential way the nonlinear deformation, induced by the generation of lift (propulsion phenomenon), and the acoustic power emitted (vibroacoustic phenomenon) of a non-cavitating flexible marine propeller blade. For a given incident flow, the deformation of an aluminum blade is much smaller than that of a composite blade. The composite blade’s deformation has a significant positive impact on lift generation whereas the deformation of the aluminum blade tends to reduce traction. The dynamic characteristics of the aluminum blade at rest and under the fluid induced static load are similar, while those of the composite blade are very different in these two cases. The simplified two-step approach proposed in this study is therefore useful to accurately assess the emitted sound power by the vibrating blades.