Skip to content

Home > Introduction > Input & Output Files > FE Engine Input & Output Files

Solver input/output files

The different input files required to run DeepLines solver and the output files produced during the calculation are detailed below.

  • Analysis input file (.LOG): This ASCII file contains all the input data required to run a given analysis with the solver. Each file consists in series of keywords and related parameters. Each keyword is preceded with the "*" character.

  • Hydrodynamic database file (.HDB): This file is an input file used only in the case a floater is included in your analysis. It contains all the hydrodynamic properties required to derive the floater's motion. This file is created by the GUI and placed by default in a sub-directory named 'HDB', located in the folder that contains your .DSK model file. This directory must always be placed beside the .LOG file prior to running the solver.

  • Calculation history file (.DAY): This file provides basic information about convergence, and is displayed in the GUI as the calculation progresses. See an example file.

    cpu time - initialisation       :        0.05 s :         0.02 seconds of user time                                                          0.03 seconds of system time <----- processing by the solver of the input file
\- Loop on the contacts positions      nitcon =    1 <----- maximum number of iteration on contact position
\- Loop on the contacts directions     nitnor =    1 <----- maximum number of iteration on contact direction
\- Newton-Raphson loop                 nitnew = 1000 <----- maximum number of iteration for the newton algorithm
\*\*  Beginning of the cable interface analysis
istep =   0  idecon =    1  itenor =   1  itenew =    6  nbcont\_tot =     0  active\_nbcont =     0
\*\*  End of the cable interface ==> converged <----- Static calculation with all elements considered as cable to obtain an optimized initial condition for the beam calculations
\- Loop on the contacts positions      nitcon =    1
\- Loop on the contacts directions     nitnor =    1
\- Newton-Raphson loop                 nitnew = 1000 <----- Static calculations with beam elements, same maximum number of iterations as for the cable interfacing
\*\*  Beginning of the analysis step :    0
istep =   0  idecon =    1  itenor =   1  itenew =    9  nbcont\_tot =     0  active\_nbcont =     0
\*\*  End of the analysis step :    0 ==> converged -    9 iterations <----- first iteration step for the static analysis, 9 iterations are performed to reach convergence, there is no potential contact (and therefore no active contact elements)
\*\*  Beginning of the analysis step :    1
istep =   1  idecon =    1  itenor =   1  itenew =    2  nbcont\_tot =     0  active\_nbcont =     0
\*\*  End of the analysis step :    1 ==> converged -    2 iterations
.
.
.
\*\*  Beginning of the analysis step :    5
istep =   5  idecon =    1  itenor =   1  itenew =    2  nbcont\_tot =     0  active\_nbcont =     0
\*\*  End of the analysis step :    5 ==> converged -    2 iterations <----- last iteration step
cpu time - static calculations  :        0.11 s :         0.11 seconds of user time                                                          0.00 seconds of system time <----- CPU time for the static anlysis
\*\*  Beginning of the dynamic analysis <----- dynamic analysis
\- Loop on the contacts positions      nitcon =    1
\- Loop on the contacts directions     nitnor =    1
\- Newton-Raphson loop                 nitnew =   30 <----- maximum number of iterations in dynamic
t =       0.00001    dt =  0.10000    itconv =     2    nbcont\_tot =      0  active\_nbcont =     0 <----- time, timestep and number of iterations to reach convergence
t =       0.20001    dt =  0.10000    itconv =     2    nbcont\_tot =      0  active\_nbcont =     0
.
.
.
t =      19.90001    dt =  0.10000    itconv =     2    nbcont\_tot =      0  active\_nbcont =     0
t =      20.00001    dt =  0.10000    itconv =     2    nbcont\_tot =      0  active\_nbcont =     0
\-----------------
Number of time step increases :     0
Number of time step decreases :     0
Number of time step divisions :     0
Number of time step changes :     0 <----- statistics on adaptive time step if required
\-----------------
Total number of time steps :   200
Mean time step :  0.10000
\-----------------
\*\*  End of the dynamic analysis ==> converged
cpu time - dynamic calculations :        2.60 s :         1.88 seconds of user time                                                          0.72 seconds of system time
cpu time - total simulation     :        2.85 s :         2.04 seconds of user time                                                          0.81 seconds of system time <----- Total CPU time

\--------------------------------------------------
Normal : the requested calculations are finished
\--------------------------------------------------<----- end of calculation

  • Calculation detailed listings (.LIS): This file contains detailed information about the calculation, including full details about convergence, reaction forces and error messages. See more details:

    This file provides very extensive details on the analysis. The header contains the DeepLines version used to perform the analysis as well as the date of the analysis, followed by a copy of the input file (.LOG).

    If any error is detected, a message is written in the .DAY file. In the .LIS file, a message is written after the keyword that the solver was unable to translate. A consistency error might also be found, for instance, if you define a VIV analysis without current. The .LIS file summarizes all the quantities used by the solver, the properties of all the elements, the environmental data, …, and the analysis convergence results. A non-exhaustive list of headers that are found in the .LIS files is:

    • physical constants
    • material properties
    • original coordinates
    • element data
    • Group of elements
    • Contacts between groups
    • waves
    • current
    • nodal data
    • general parameters for calculations

    For each load step (static) and time-step (upon request), the details of the convergence algorithm

    load step nr.     0

    ------------------

      itera   qmax1       fmax1     noeud dir.
1   0.216E+06   0.309E+06    38    3
2   0.470E+06   0.673E+06    37    3
3   0.155E+05   0.119E+06    37    3
4   0.364E+04   0.119E+06    37    3
5   0.366E+03   0.119E+06    37    3
6   0.418E+01   0.119E+06    37    3

\----> converge reached for forces

        dxm1        xmax1

      0.321E-05   0.300E-02

        ----> converge reached for displacements

    Value of each degree of freedom at convergence

    • forces in elements
    • reaction forces at boundary conditions
    • and more, depending on your type of analysis.

Tip

In case your analysis fails to run properly or an error message displays in the .DAY file, it may be extremely useful to open the corresponding .LIS file and look for 'error' to get details about what occurred during the analysis.

  • Group of elements files (.TXT): This file contains information about the group of finite elements defining any riser, mooring line or surface. See an example file corresponding to a riser.

    Group number    1
\[Properties for external efforts\]
Abscissa     Z coord   Element   Length  Dry weight  Wet weight   DiamH   DiamB     Pext       Pint
(m)            (m)       (-)        (m)     (kN/m)      (kN/m)     (m)      (m)     (MPa)      (MPa)      
1.000       -0.974       1      2.000  1.472E+00   1.156E+00   0.2000   0.2000  1.098E-01  1.096E-01
3.000       -2.922       2      2.000  1.472E+00   1.156E+00   0.2000   0.2000  1.294E-01  1.287E-01
5.000       -4.867       3      2.000  1.472E+00   1.156E+00   0.2000   0.2000  1.489E-01  1.477E-01
.
.
.
\[Properties for internal efforts\]
Abscissa     Z coord   Element   Length     OD        EA        EI        GCt
(m)            (m)       (-)        (m)     (m)       (N)       (Nm2)     (Nm2)
1.000       -0.974       1      2.000   0.2000  1.000E+09  1.000E+06  1.000E+07
3.000       -2.922       2      2.000   0.2000  1.000E+09  1.000E+06  1.000E+07
5.000       -4.867       3      2.000   0.2000  1.000E+09  1.000E+06  1.000E+07
7.000       -6.810       4      2.000   0.2000  1.000E+09  1.000E+06  1.000E+07
9.000       -8.751       5      2.000   0.2000  1.000E+09  1.000E+06  1.000E+07
.
.
.
\[Internal pressure definition \]
Reference node     1
Internal fluid specific gravity :  1.0000 (-)
Added pressure :  0.100E+06 (Pa)

  • Quasi-Static analysis results database (.DTBS): This binary file contains all the results from your quasi-static analysis (position of nodes).

  • Time-domain dynamic analysis results database (.DTB): This binary file contains all the results from your dynamic analysis (position of nodes).

  • Frequency-domain dynamic analysis results database (.DTBF): This binary file contains all the results from your dynamic analysis (position of nodes).

  • Modal analysis results database (.DTBM): This binary file contains all the results from your modal analysis.

  • VIV analysis results database (.DVS): This binary file contains all the results from your VIV analysis with DeepVIV.

  • Plastic component of curvature database (.DTP): This binary file is created only in case a non-linear curvature/bending moment law is used (typically for unbounded flexible pipes). When such a law is used, the position of nodes is not sufficient to derive the bending moment components, which require an additional parameter to be stored. This file contains the accumulated plastic curvature and center of the plasticity criterion. These data allow to build the global bending moment and  use the restart option.

  • Reaction forces databases (.DTBRS and .DTBR): These binary files are created by the solver to store static and dynamic reaction forces along the lines components. Output for reaction force will be available from the GUI in the “Static curves” and “Dynamic curves” post-processing panel. Six quantities are stored in the database file : X-Y-Z reaction forces and X-Y-Z reaction moments.

  • Contact results databases (.DTBSC and .DTBC): These binary files are created by the solver to store static and dynamic contact results. Results stored for each type of contact include : Contact energy, contact reaction force, axial friction force, lateral friction force, trench induced resistance force and friction induced moment.

  • Cable post-processing mapping file (.CAN): The file gives the number first node of the element together with its position. It will provide a mapping for the interface to know that node i is the first element of cable j. It also indicates that forces for node i coming from cable element j are stored at line j of the block containing all cable elements at a given iteration or time step. The interface will have to load the file information when loading the .dss.

  • Cable static post-processing file (.CAS): This file is used to post-process the internal loads along cable elements from quasi-static analyses. This files contains the internal loads along the X, Y and Z global axes as a function of the quasi-static analysis step.

  • Cable dynamic post-processing file (.CAD): This file is used to post-process the internal loads along cable elements from dynamic analyses. This files contains the internal loads along the X, Y and Z global axes as a function of the time.

  • Cable modal and frequency post-processing file (.CAF): This file is used to post-process the internal loads along cable elements from modal and frequency-domain dynamic analyses. This files contains the stiffness matrix components for all cable elements. 

Tip

When facing convergence troubles, it may be useful to visualize the intermediate solutions corresponding to each iteration in the Newton-Raphson algorithm. To do so, you must activate the option named "Save non-converged solutions" from the Static Calculation Parameters form associated with the analysis.

An additional database file (.DTBI) will then be created during the computation. Open the .DSS file once the quasi-static analysis is complete (or failed) with the GUI to visualize the non-converged intermediate positions within the 3D View window.