Fully-Coupled Nonlinear 3-D Time-Domain Simulation of Drilling Dysfunctions Using a Multi-Body Dynamics Approach

2015 ◽  
Author(s):  
Andrew S. Elliott ◽  
Mark Hutchinson
Keyword(s):  
Time Domain ◽  
Time Domain Simulation ◽  
Body Dynamics ◽  
Multi Body ◽  
Fully Coupled

Simulation of Dynamic Tracking System for Rescue at Sea

2015 ◽  
Author(s):  
Qian Shi ◽  
Shixiao Fu ◽  
Ning Deng ◽  
Jinsong Xu
Keyword(s):  
Time Domain ◽  
Pid Control ◽  
Tracking System ◽  
Wave Loads ◽  
Time Domain Simulation ◽  
Empirical Formulas ◽  
Dynamic Tracking ◽  
Control Target ◽  
The Time Domain ◽  
Multi Body

In this paper, a time domain simulation is established to investigate the feasibility of a PID controller for rescue at sea. In the problem, the endangered ship loses its power and moves freely under environmental forces. The control target for Dynamic Tracking (DT) is to maintain a certain distance between the endangered and rescue ships. The time domain simulation includes multi-body hydrodynamics and Guidance Navigation Control (GNC) system. The multi-body hydrodynamics is modeled with the ship-ship interaction considered. The first and second order wave loads, added mass and damping in frequency domain is calculated using potential theory. Current and wind loads are estimated by empirical formulas summarized from experimental data. As for the design of the GNC system, PID control strategy is applied for the controller and the Kalman Filter for the observer. The time domain simulation in this research is performed in MATLAB.

Time Domain Turret Load and Motion Analyses for a FPSO

2020 ◽  
Author(s):  
Hyoungchul Kim ◽  
Bonjun Koo ◽  
Johyun Kyoung
Keyword(s):  
Time Domain ◽  
Interaction Model ◽  
Hydrodynamic Interactions ◽  
Test Results ◽  
Mechanical Coupling ◽  
Body Interaction ◽  
Nonlinear Springs ◽  
Frictional Damping ◽  
Multi Body ◽  
Fully Coupled

Abstract Fully coupled time domain turret/FPSO simulations are conducted using TechnipFMC proprietary software MLTSIM. To analyze hydrodynamic interactions and mechanical coupling effects between an FPSO and its turret, a multi-body interaction model is developed and analyzed. In the multi-body interaction model, full coupled hydrodynamic interactions are considered, and the bearing connections are modeled with nonlinear springs and frictional damping. The global performance analysis results are systematically compared with model test results (Kim et al. [1]), and hydrodynamic loads and mechanical coupling loads on the turret are presented in this paper.

scholarly journals Fuel-Optimal Thrust-Allocation Algorithm Using Penalty Optimization Programing for Dynamic-Positioning-Controlled Offshore Platforms

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2128 ◽  
Author(s):  
Se Kim ◽  
Moo Kim
Keyword(s):  
Quadratic Programming ◽  
Time Domain ◽  
Dynamic Positioning ◽  
Positioning System ◽  
Time Domain Simulation ◽  
Allocation Algorithm ◽  
Dynamic Positioning System ◽  
Fully Coupled ◽  
Pseudo Inverse ◽  
Thrust Allocation

This research, a new thrust-allocation algorithm based on penalty programming is developed to minimize the fuel consumption of offshore vessels/platforms with dynamic positioning system. The role of thrust allocation is to produce thruster commands satisfying required forces and moments for position-keeping, while fulfilling mechanical constraints of the control system. The developed thrust-allocation algorithm is mathematically formulated as an optimization problem for the given objects and constraints of a dynamic positioning system. Penalty programming can solve the optimization problems that have nonlinear object functions and constraints. The developed penalty-programming thrust-allocation method is implemented in the fully-coupled vessel–riser–mooring time-domain simulation code with dynamic positioning control. Its position-keeping and fuel-saving performance is evaluated by comparing with other conventional methods, such as pseudo-inverse, quadratic-programming, and genetic-algorithm methods. In this regard, the fully-coupled time-domain simulation method is applied to a turret-moored dynamic positioning assisted FPSO (floating production storage offloading). The optimal performance of the penalty programming in minimizing fuel consumption in both 100-year and 1-year storm conditions is demonstrated compared to pseudo-inverse and quadratic-programming methods.

Development of a Multi-Body Vessel Dynamics Simulation Tool

2009 ◽  
Author(s):  
Xiaochuan Yu ◽  
Chandan Lakhotia ◽  
Jeffrey M. Falzarano
Keyword(s):  
Time Domain ◽  
Wave Force ◽  
Dynamics Simulation ◽  
Simulation Tool ◽  
Sea State ◽  
Body Dynamics ◽  
Constant Coefficients ◽  
The Time Domain ◽  
Multi Body ◽  
The Given

Multi-body dynamics is important in many fields of engineering. For the at-sea transfer of cargo between ships multi-body dynamics is particularly important. There are several methods of transferring solid cargo between vessels and these include by crane or by ramp. Each method is extremely sensitive to the relative motions between the various vessels. An accurate modeling of the vessels’ motions is critical in determining limiting sea state conditions and in suggesting how to improve the given system. There are various levels of approximation which are commonly employed to model vessel hydrodynamics and we hope to eventually determine what level of approximation is appropriate for a given situation. In this paper, we will compare the effects of considering as well as ignoring the multi-body hydrodynamic interactions using a constant coefficients approximation to the time domain radiated wave force.

Time-Domain Simulation of a Multi-Body Floating System in Waves

2010 ◽  
Author(s):  
Xiaochuan Yu ◽  
Jeffrey M. Falzarano ◽  
Zhiyong Su
Keyword(s):  
Time Domain ◽  
Impulse Response Function ◽  
Hydrodynamic Interactions ◽  
Time Domain Simulation ◽  
Single Vessel ◽  
Close Proximity ◽  
Floating System ◽  
Response Amplitude Operators ◽  
Multi Body ◽  
Coefficient Method

It is important to study multi-body dynamics when analyzing the transfer of cargo between ships and platforms at sea. The hydrodynamic interactions should be considered in an accurate way to predict the relative motions between them. In this paper, the response amplitude operators (RAOs) of a single vessel will be compared with those of a multi-body system, considering different spacing between them. Further, the coupled hydrodynamic interactions among multiple vessels in close proximity are studied. Various levels of approximation, including the constant coefficient method (CCM) and the impulse response function (IRF) method, are employed to model the hydrodynamic interactions. Finally, the comparison between a single vessel and multi-body time domain simulation is also given.

scholarly journals Combining Multi-body Dynamics and Potential Flow Simulation Methods to Model a Wave Energy Converter

2018 ◽  
Author(s):  
Christopher McComb ◽  
Michael Lawson ◽  
Yi-Hsiang Yu
Keyword(s):  
Frequency Domain ◽  
Wave Energy ◽  
Time Domain ◽  
Domain Boundary ◽  
Flow Simulation ◽  
Primary Objective ◽  
Boundary Integral ◽  
Body Dynamics ◽  
Numerical Tool ◽  
Multi Body

Numerical simulations that predict the dynamics and performance of wave energy converters (WECs) require the simulation of complex fluid-structure interactions between a WEC device and the wave environment. Navier- Stokes computational fluid dynamics (CFD) simulations and fully time-domain boundary integral equation methods (BIEMs) can be coupled with multi-body dynamics solvers to simulate these problems. However, the computational resources that are required to perform these types of high-fidelity simulations are significant, precluding the use of CFD and time-domain BIEM for design optimization. One method for reducing the numerical complexity of WEC simulations is to model the hydrodynamics using frequency- domain simulations, while model the dynamic motion of the WEC device in the time-domain using multi-body dynamics methods.The primary objective of the work presented herein is to develop such a numerical tool using the multi-body solver SimMechanics and the frequency-domain hydrodynamics code WAMIT. The numerical tool was developed so that WEC devices comprised of arbitrarily connected bodies, power-take-off (PTO) systems, and mooring systems can be simulated in operational sea states, where the wave environment can be modeled under linear assumptions. The remainder of this paper describes the development and verification of the numerical tool.

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