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Overview

DeepLines History

DeepLines is part of the marine software solutions developed by Principia in collaboration with IFP Energies Nouvelles. The software is based on the finite elements method (FEM) and forms an integrated solution to perform in-place and installation analyses of a wide range of offshore systems based on a long term background and a large track record. Indeed, This numerical tool is based on the program Flexan, initially developed for flexible risers and used from 1980 by Coflexip Stena Offshore (CSO) for their designs. At that time, compared to existing tools dedicated to fixed offshore structures, the main challenge is to capure the risers' dynamic behaviour which induces geometrical non-linearities. Actually, risers are "slender" structures that means that one dimension (their axes) is much larger than the other ones defining their cross sections. Therefore, the deformations of the section are assumed negligible and the mechanical behavior is mainly governed by axial strains which provides the risers lateral stiffness. After that, DeepLines field of application has been extended to perform conceptual, basic and detail design of different "slender structures" in the Oil & Gas industry: offloading lines, rigid production risers, umbilcals, drilling risers, hoses and also mooring lines... In the 90ies, the DeepWater context requires the introduction of coupled simulations for the overall analysis of a Floating Production System. To do so, DeepLines was closely coupled with Diodore, the diffraction/radiation solution developed by PRINCIPIA, to take into account during the simulation the interactions between any floating unit and its mooring lines or risers. External links with other diffraction/radiation softwares were also made possible defining an ASCII format file to generate a hydrodynamic database (HDB file). At last, to address the needs for an overall design tool raised by the development of offshore windturbines platforms, a new module DeepLines WIND was created in 2011. For that purpose, DeepLines structural model was extended to handle wind turbine specificities, specifically for the modelling of blades and rotors rotation and several BEM models were implemented in an external DLL to calculate the aerodynamic loads. Since 2013, a so-called WIND module, developed by IFP Energies Nouvelles, is available with DeepLines to model wind turbine both in terms of aerodynamic loads and control. It is referred to as DeepLines Wind. This is specifically designed to perform coupled analysis of offshore (floating or fixed) wind turbines.

Types of analyses

The following type of anlayses can be performed :

  • Static and quasi-static analysis,

  • Time-domain dynamic analysis,

  • Frequency domain dynamic analysis (for not rotating wind turbine),

  • Design of drilling riser based on API RP 16Q,

  • Modal analysis of complete risers and mooring systems,

  • VIV prediction models (both modal and time domain approaches),

Key features

  • Time-domain and frequency domain dynamic analyses can both be run from the same GUI,

  • Powerful and robust finite elements method including coupled bending/torsion effects,

  • Wide range of boundary conditions,

  • Non-isotropic 3D seabed friction and suction effect,

  • Wake models to assess drag loads on lines,

  • Modeling of sliding device including friction : J-tube, guides, keel-joint, PIP, ...

  • External contact between lines for clashing analysis,

  • Contact with any user-defined surface, either fixed or moving (soil, moonpool, bellmouth,... )

  • Automated detection of contact zones based on proximity criteria,

  • Non-linear bending stiffness including hysteresis effect for modeling unbounded flexible pipes,

  • Includes the effect of thermal loads for any type of temperature profile,

  • Multi-linear stiffness for risers and specific elements to model synthetic ropes,

  • DNV-OS-F201 and DNV-OS-F101 unity checks are available straight from the user interface,

  • Assessment of in-line VIV response of pipeline span according to DNV-RP-F105,

  • Structural code check for structures modelled by beams.

User interface

  • Intuitive user interface including a model browser and 3D view window allowing very efficient model set-up and straight access to analyses results

  • Project-oriented model files including all input data and parameters required to run several analyses from the same model file

  • Batch processing form enabling automation of large sets of simulations

  • Multi-threaded execution of analysis and post-processing tasks

  • Easy access to all model data, copy/paste facilities

  • Post-processing of a wide range of results for risers, moorings and floating supports : tension, stress, curvature, built-in angles, tensioner strokes, deformed shapes, iso-angle curves for TTRs

  • Batch post-processing facilities

  • Clearance post-processing form

  • Automated export of results to ExcelTM nd export of AVI files from the 3D View window

  • Statistics on every graphs

  • Fatigue analysis of steel risers and mooring lines

  • Export of .MDS modal database files for input to SHEAR7

VIV analysis add-on module

  • Prediction tool of Vortex-Induced Vibrations,

  • Static and modal pre-analysis,

  • Lock-in zones and structural response amplitude,

  • VIV fatigue estimate based on SN curves,

  • Modified drag coefficient,

  • Analysis of VIV suppression devices

Fatigue damage processor add-on module

Post-processor to determine the fatigue life of homogenous risers, mooring lines and Trelline bonded hoses:

  • Based on the summation of damage due to various sea-states with their probability of occurrence,

  • Spectral analysis based on regular wave time-domain analyses; Stress RAO extracted from time series.

  • Rainflow method for irregular waves,

  • Damage calculated along the riser at several points on the circumference.