Time-domain, shallow-water hydroelastic analysis of VLFS elastically connected to the seabed

Abstract

In order to ensure the safe operation of a VLFS, a combination of mooring, breakwater and other motion reducing systems is employed. In the present work, the transient hydroelastic response of a floating, thin elastic plate, elastically connected to the seabed, is examined. The plate is modelled as an Euler-Bernoulli strip, while the linearized shallow water equations are used for the hydrodynamic modelling. Elastic connectors are approximated by a series of simple spring-dashpot systems positioned along the strip. A higher order finite element scheme is employed for the calculation of the hydroelastic response of the strip-connector configuration, over the shallow bathymetry. After the definition of the initial-boundary value problem, its variational form is derived and discussed. Next, on the basis of the aforementioned formulation, an energy balance expression is obtained. The effect of variable bathymetry on the response of a two connector-strip system, is examined by means of three seabed profiles, featuring a flat bottom, an upslope and a downslope environment. For the flat bottom case, the strip response mitigating effect exerted by the employment of two and three elastic connectors is considered. Finally, by means of the derived energy balance equation, the energy exchange is monitored, providing a valuable insight into the transient phenomena that take place in the studied configurations.

Scaling strategies for multi-purpose floating structures physical modeling: state of art and new perspectives

“…Fully-elastic structures (L > LC) must be scaled taking into account the structure flexibility. Numerically, such structures are usually represented by means of simplified elastic isotropic beam [77,78] or plate [79,80] models. In both cases, assuming that the external geometry is scaled by means of Froude laws, the key parameter for the representation of the elasticity is the equivalent bending stiffness EI, with scaling factor λL 5 .…”

Resonances of enclosed shallow water basins with slender floating elastic bodies

“…Future work is planned towards the development of such a model, based on the variational form presented in sections 3 and 5. A 2D Finite Element method of this kind can be used for the simulation of multiple floating plates of irregular shape, incorporating the effects of variable bathymetry, variable plate properties and simple anchoring configurations [34]. It is envisioned that this new methodology will constitute an efficient tool for the analysis of demanding problems of VLFS hydroelasticity [35] like the hydroelastic resonant behaviour of closed basins.…”

A monolithic finite element formulation for the hydroelastic analysis of very large floating structures

“…The former assumes a linear response of the transient effects described as a time‐harmonic motion, see for instance References 28‐30. The time‐domain analysis avoids the linear assumption, making it a suitable approach for the analysis of steep wave fronts and cases with highly nonlinear effects 13,31 . In this work we develop a formulation that is suitable for both approaches, frequency and time domain.…”

“…The time-domain analysis avoids the linear assumption, making it a suitable approach for the analysis of steep wave fronts and cases with highly nonlinear effects. 13,31 In this work we develop a formulation that is suitable for both approaches, frequency and time domain.…”