FRyDoM
Flexible and Rigid body Dynamic modelling for Marine operations (FRyDoM)
FRyDoM (Flexible and Rigid body Dynamics modeling for Marine operations) is an open source multi-physics simulation framework dedicated to the simulation of complex marine systems developed during a joint research project between D-ICE ENGINEERING and Ecole Centrale de Nantes since 2016.
Being built on top of PROJECTCHRONO middleware, a general open-source multi-physics engine, FRyDoM is able to simulate multidody dynamic systems of arbitrary topologies composed of rigid and flexible bodies - using a nonlinear finite element engine - along with collision detection and nonsmooth contact modelling techniques. Most of the development about FRyDoM were to provide state-of-the-art capabilities in term of marine environment modelling (irregular sea states, wind and current fields) along with associated interactions with marine systems regarding seakeeping, manoeuvring, wind loads, marine propellers and steering systems modelling of any kind, wind propulsion system modelling, up to mooring system modelling with static or dynamic mooring lines for station keeping. FRyDoM also internally interfaces to D-ICE control systems for autopilot or dynamic positioning systems. The main goal of FRyDoM, as a framework, is to provide quick means to develop specialized marine simulation solutions, for a broad wide range of ad-hoc applications, without having to reinvent the wheel for common modelling needs in marine engineering.
Most recent developments are focused on optimization of the computational efficiencies of the hydrodynamic models, implementations and solvers towards real-time applications such as marine training simulators and O&M monitoring.
FRyDoM philosophy
From the outset, FRyDoM was imagined as a framework and not as software. This means that FRyDoM is intended to be the cornerstone of tailor-made numerical applications for the dynamic modelling and simulation of complex marine systems.
The purpose of the FRyDoM framework is to provide the keys for developing specific and ambitious programs for the simulation of complex marine systems. The general idea behind the design of FRyDoM is to avoid presupposing the type of application it can be used for. As soon as the aim is to simulate a system at sea, whether it's a complex articulated floating multi-body system, with or without contact, with cables, thrusters, or steering system, with constraints on calculation precision or rather on execution speed, FRyDoM has been designed to ease the development of a specifically adapted tool. FRyDoM's software architecture is also designed to facilitate its extension to new physical models as required.
A prerequisite for using FRyDoM is therefore to be an engineer who masters both object-oriented programming in C++ and the basis of the physical models proposed, such as hydrodynamics or marine environment modelling. At this price, FRyDoM opens an ocean of numérical possibilities, from the deployment of complex engineering workflows on supercomputers to real-time applications.
Programming skills and engineering ideas are the limits.
General Features
A multiphysics Engine for marine systems focused on high-fidelity
Based on PROJECTCHRONO (marinization)
Constrained multibody dynamic solver
Embedded finite elements solver
State of the art collision detection algorithms
Smooth and nonsmooth contact handling
Marine environment modelling
Advanced hydrodynamics (wave interaction, resistance, manoeuvring...)
Advanced control systems
Propulsion
Cable modelling & complex mooring (Catenary static and FEA dynamics)
Embeddable framework
CMake / C++17
Industrial-grade Software (Gitlab, CI, unit testing etc...)
Examples of industrial/commercial application cases where FRyDoM is used by D-ICE ENGINEERING:
Floating wind turbine modelling with tight coupling with OpenFAST for blade controller setting
Study of the motion of floating wind turbines moored to a quay
Dynamic performance prediction of Wind Assisted Vessels for different industrial sail systems
Physics engine for training simulator focused on Wind Assisted Vessels
Manoeuvring simulations for model identification based on CFD calculations
Crew Transfer Vessel boat landing operation on Offshore Wind Turbines performance prediction
Physics engine for Dynamic Positioning algorithm development
etc.
Hydrodynamics models
Manoeuvring
Calm water resistance
One quadrant Abkowitz model adapted to autopilot simulations
Full four quadrant model for Dynamic Positiong and harbour manoeuvring simulations
Wave structure interactions
First order wave excitation and radiation based on Hydrodynamic Databases generated by potential theory hydrodynamics solvers
Multibody wave interactions
Finite and infinite water depth
Ultra fast radiation memory effect calculation (Cummins formulation) based on in-house original frequency domain identification of radiation frequency response
Second order mean drift effects
Forward speed effects based on encounter frequency and modification of the memory effects
Full Morison elements for slender bodies
Additional damping (eg nonlinear roll damping)
Wave modelling
Regular waves
Irregular waves with directional spreading including different standard wave spectrum (Pierson-Moskowitz, JONSWAP, ...)
Stretching functions for better wave orbital velocity calculations
Hydrostatics
Linear modelling
Nonlinear modelling based on instantaneous clipping of mesh with respect to undisturbed wave field
The principal source for technical information about FRyDoM capabilities is its theory guide which is freely available on the following link. It also includes V&V cases against literature and other related software.