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4  GROUP A—PROBLEM TYPE AND DIMENSIONING

A.10


Object:


The keywords of this group enable the definition of the problem, and the dimensioning (memory allocation) of the computation.


Comments:


These keywords are described in detail in the following pages.

4.1  TITLE AND PRELIMINARY INFORMATION

4.1.1  TITLE

A.20


The title, composed of a maximum of 72 characters, is the first card of the data set and is compulsory.


The contents of this data card is printed at the top of each page edited by EUROPLEXUS together with the date of the run.

4.1.2  INPUT DATA ECHO AND INPUT CHECK UP


Object:


These keywords are used to obtain an echo on the terminal or console window of the input data being precessed and to check up the syntactical correctness and the coherence of the data.


Syntax:
                < $[ "ECHO" ; "NOEC" ]$ >

Comments:


The "ECHO" optional keyword produces an echo on the screen or terminal of the input file directives as they are being processed. If the input file is very long, this may be annoying. By default no echo is produced. See also the option OPTI ECHO, Page H.50, which may be used at any point of the input file after the dimensioning.


The "NOEC" optional keyword disables the echo on the screen or terminal of the input file directives as they are being processed. By default no echo is produced. See also the option OPTI NOEC, Page H.50, which may be used at any point of the input file after the dimensioning.

4.2  INTERACTIVE (FOREGROUND) EXECUTION

A.25


Object:


The CONV directive can be used to execute EUROPLEXUS interactively, i.e. in the foreground (as opposed to the default batch or background execution). In this execution mode, the user pilots the advancement of the computation, and the results at selected time instants can be either visualized on graphic screens of various types (on-screen rendering), or be stored in graphic files of various types (off-screen rendering), including animation files.


Syntax:
< "CONV"   $[ "TEKT" ; "WIN" ; "PS" ; "MIF" ]$ >


TEKT

Tektronix 4014 screen (PLOT-10 graphics language).
WIN

MS-Windows graphics (QuickWin or OpenGL). Note that OpenGL may be supported also on non-Windows platforms, e.g. on Linux.
PS

PostScript (but see also the TRAC PS interactive command).
MIF

FrameMaker MIF (but see also the TRAC MIF interactive command).

Comments:


When interactive execution is chosen, EUROPLEXUS reads the input data-set as usual, performs step 0 to initialise the computation, then prompts the user for commands from the keyboard with the phrase: COMMANDE ?.


The user can then issue various commands and subcommands typically from the keyboard in order to pilot the computation. For example, he can ask the program to perform a certain number of steps, then to pause again for further commands. Each time the calculation is paused, the current computational model can be visualized (e.g. by means of the built-in OpenGL-based visualization module) and information concerning the computation (time step, CPU time, etc.) can be printed. Furthermore, the current time step can be varied by the user.


As an alternative to typing commands by hand from the keyboard, such commands may be included in the regular EUROPLEXUS input file by enclosing them into a special directive PLAY ... ENDPLAY as described in Section 13.6 (Page I.24) and in Section 14.7 (Page ED.140).


All EUROPLEXUS interactive commands are described in detail in Section 15 (Group O).

4.3  FILE MANAGEMENT

A.27


This Section gives some information about the management of files related to the EUROPLEXUS program.


4.3.1  DEFAULT FILE NAMES


The code tries whenever possible to use default values both for the file names that it needs during the calculation, and for the associated logical unit numbers.

The idea is that logical unit numbers (a concept specific only to FORTRAN) are irrelevant for the user and should be totally transparent to him or her. What does matter for users is file names.

In many cases the code helps users by providing default values for such names (the behaviour may depend on the platform, though, see below). Of course, users are free to choose file names (and even unit numbers) if for any reason they find such defaults inconvenient.


Default names under MS-Windows

Under the MS-Windows platform default file names are built automatically by the code by using the base name of the (main) input file used in the run.

For example, suppose that the main input file is called test01.epx and resides on a directory D:\Work. The user may launch the program for example by opening a console window on the directory D:\Work (i.e., such that D:\Work is the current directory) and by typing a command such as:

  epx_bench -l test01

The actual command may vary depending on the implementation.

The code interprets the name passed on the command line (after removing any options such as the -l above) as the name of the main input file. It removes the extension .epx from this name, if present, and uses the resulting string as the base name for default file names. Thus, the user may give a full file name, complete with its path, if preferred.

Suppose now that for run test01 the user needs to read a CASTEM 2000 mesh and wants to produce results for ALICE TEMPS and CASTEM 2000.

The first task may be accomplished by the CAST directive (see page A.30). If the mesh file is formatted, and the global (main) mesh object is called model, this directive may take any of the following forms:

  1.   CAST FORM `test01.msh' model

  2.   CAST FORM 9 model

  3.   CAST FORM model

In the first form, the file name containing the mesh is given explicitly. The code associates this name to the default unit number, which for CASTEM mesh reading is number 9.

In the second form, the unit number is given explicitly. The code uses the given number as unit number and opens a file without specifying its name. This results in different behaviour depending on the platform. Under MS-Windows, a file fort.9 is opened.

In the third form neither the name nor the unit number are specified. The code uses the default file name (test01.msh in this case) and the default unit number (9).

It is clear that, whenever possible, the third form is preferable. This requires, however, that the mesh file name matches the main input file name (and is on the same directory).

When either of these conditions is impractical, the first form should be used by preference (name chosen by the user, unit number chosen by default by the code).

The second syntax is obsolete and should be avoided in new inputs.


The task of producing results files may be accomplished similarly, by the ECRI directive (see page G.70). For example, for the ALICE TEMPS output, this directive may take any of the following forms:

  1.   ECRI FICH ALIC TEMP 'test01.alt' /CTIME/ . . .

  2.   ECRI FICH ALIC TEMP 11 /CTIME/ . . .

  3.   ECRI FICH ALIC TEMP /CTIME/ . . .

Default names under Unix

Under the Unix platform(s), the same concepts apply as seen above.

Let us assume for example that the main input file is called test01.epx and resides on a directory /u/user/My_dir. The user may run the program starting from his work directory (My_dir) by the command:

  europlexus test01.epx

The mesh file will be sought in this directory under the name test01.msh. If some other input files are required, they will also be sought in this directory, under the same name but a different extension. The same rule applies to output files, in particular to the listing file.

However, for reasons related to efficient exploitation of disk space, output files may of course be directed to special directories. It is therefore recommended to contact your system administrator to learn about local disk space policies.


Alternatives under MS-Windows

Under the MS-Windows platform, there exist other ways of launching the program, alternative to the one (command line) assumed in the above example.

For example, a user might double click on the EUROPLEXUS executable or on an icon (shortcut) to this executable, or on the input file test01.epx (provided file association is used), etc.

Whenever a file name is not directly available (like in the first two alternative methods listed above), the program prompts interactively the user for such a name. The behaviour is thereafter identical to the case of command-line execution.


Comments:

Currently, default file names are available for the following directives:

4.3.2  EXPLICIT FILE OPENING

A.28


Object :


This directive allows to open a file directly from the input data, by specifying its logical unit number and its name.

It may be used whenever either the user wants to override a file choice made by default by the code (example: a very long calculation requires its results file to be written to a remote disk, due to space problems), or to force opening of a unit that is otherwise not opened by the code.

Note, however, that including this directive in input files generally renders them not portable across different platforms or even different machines belonging to the same platform. In fact, absolute (full) file names are usually required.

For this reason, it is preferable to use the short file name syntax (or even the default name syntax) described in the previous sections whenever possible.


Syntax
      "OPNF"  < "FORMAT" ; "WXDR" ; "RXDR" >  nfic  'nomfic'


FORMAT

Specify that formatted file is required. By default, the file is unformatted.
WXDR

Specify that XDR writeable file is required. For the output "K2000" file for example.
RXDR

Specify that XDR readable file is required. For the input mesh file for example.
nfic

Logical unit number of the file.
’nomfic’

File name.

Comments :


It is forbidden to open explicitly the logical unit numbers 0, 5, 6 and 7, that are reserved in most operating systems. Other unit numbers reserved by EUROPLEXUS are 15, 16 and from 91 onwards.


The way of coding the file name depends upon the operating system:

For other operating systems, please contact your system administrator.

4.3.3  EXPLICIT OUTPUT DIRECTORY DEFINITION

A.29


Object :


This directive allows to define a directory for output files.

Like for EXPLICIT FILE OPENING, the rules for the name of the given directory may vary from one platform to another.


Syntax
      "OPNF"  "DRST"  |[ 'nomdir' ; "PWD0" ]|


DRST

Following by the name of directory used for named result files (ALICE, ALICE TEMPS, K2000, INP, VTK-PARAVIEW, ...). Alias : DPRV or PATH.
’nomdir’

Name of directory used for result files.
PWD0

Directory name is the current directory.

Comments :


In the case of an UNIX system, the defined directory is an absolute path. In the case of a WINDOWS system, the directory is given as a relative path.


In both cases, if given directory does not exist, it is created.

4.4  TYPE OF MESH, PROBLEM AND LISTING

A.30 - Feb13


Object:


1/ To define the mesh type that will be used:


2/ To define the general type of computation:


3/ To define some general options about the form of printed results (useful to reduce the size of the output listing in extremely large test cases)


Syntax:

    $[
        $[ "GIBI" ; "CASTEM" ]$ <$[ "FORM" ; "XDR" ; "BINA" ]$>
                                <$[ ndis ; 'file_name' ]$>  'nomobjet' ;
        "IDEA" <$[ ndidea ; 'file_name' ]$> < "REWR" > < "MAPP" > ;
        "MEDL" 'file_name' ;
        "KFIL" 'file_name' ;
    ]$

    |[ "DPLA"  ;  "CPLA"  ;  "AXIS" <"HOLE" hole> ;  "TRID"  ]|

    < $[ "LAGR" ; "EULE" ; "ALE" ]$ >

    < "NAVIER" >   < "HOMO" nhtube >
    < "MBETON"     nssc     >
    < "FRQR"       nfrqr    >  < "SPCO" sphcon >
    < "LAGC"  >
    < "MBACON"  < "POST" > >
    < "SAUVEGARDE" ... >    < "REPRISE" ... >

    < "ADDF" < "NAVS" > < "TEMP" >  < "TURB" > >
    < "MECA" >
    < "MEDE" >
    < "EROS" <ldam>  <CROI>  <LIMI>       >
    < "RISK" < "PROB" |[ "FERR" ; "YETP" ]| >
             < "LUNG" |[ "BAKE" ; "LEES" ]| >
             < "SPLI" >
    < "SCLM" ... >
    < "BMPI" >
    < "ADAP" "MLVL" rlvl < ( 'nomelm' rlel ) > >
    < "CFVN" >


GIBI

Mesh generated by GIBI (GIBI objects will be read to define the mesh) and stored with the ’SORT’ directive (see Comments below).
CASTEM

Mesh and other characteristics (geometrical, material, champoints) generated by CASTEM2000 and stored with the ’SAUV’ directive (see Comments below).
FORM

The CAST3M generated data are to be read in formatted (ASCII) mode (this is the default).
XDR

The CAST3M generated data are to be read in XDR mode.
BINA

The CAST3M generated data are to be read in binary mode.
ndis

Number of the logical unit of the mesh file.
’file_name’

Complete path localising the mesh file, under Unix operating systems. If both this and the unit number ndis are omitted, the code chooses a name and a unit number by default (see page GBA_0027).
’nomobjet’

Name of the whole (main) object meshed by GIBI.
IDEA

Mesh generated by I-DEAS. At the moment, only formatted IDEAS files are allowed in input.
ndidea

Number of the logical unit of the mesh file.
’file_name’

Complete path localising the mesh file, under Unix operating systems. If both this and the unit number ndis are omitted, the code chooses a name and a unit number by default (see page GBA_0027).
REWR

Write a new I-DEAS file with re-ordered numbering (no holes), see details below.
MAPP

Stop run after re-writing the new I-DEAS file with re-ordered numbering, see below for details.
MEDL

Mesh described in a MED file.
’file_name’

Full path of the med file (this file contains the mesh). The key word OPEN followed by a unit number is not available to open a MED file.
KFIL

Mesh described in a LS-DYNA k-file.
’file_name’

Full path of the k-file file (this file contains the mesh).
AXIS

Axisymmetric computation.
HOLE

Optionally, for axisymmetric cases a central ’hole’ may be specified by this keyword: in this case the given hole radius is automatically added to the mesh radial coordinates given in input (this is a shorthand alternative to providing a mesh with the actual hole in it).
DPLA

Two-dimensional plane strain computation.
CPLA

Two-dimensional plane stress computation.
TRID

Three-dimensional computation.
LAGR

Computation with the Lagrangian formulation (default). All nodes are Lagrangian. The GRIL directive is not required.
EULE

Computation with the Eulerian formulation. All nodes are Eulerian. The GRIL directive is not required.
ALE

Computation with the A.L.E. formulation. The GRIL directive may be used to specify the motion of nodes (see GBINT_0018).
NAVIER

One-dimensional uncoupled calculation (fixed pipelines), with incompressible or nearly incompressible fluids. The calculation may only be done in Eulerian. Therefore, it is mandatory to specify also the directive "EUL E".
nhtube

Maximum number of tubes per unit cell (homogenised material).
nssc

Number of layers for the CMC3 element with the BETO material. By default, there is just one layer per element. This number must be between 1 and 20.
FRQR nfrqr

Frequency of searching neighbour nodes. By default = 1. This option, valid only for calculations with the NABOR or SPH methods, allows the user to considerably reduce the calculation time.
SPCO sphcon

Maximum number of retained structure faces in contact with the same SPH particle. By default it is 1, meaning that only the first contacting face is treated (the penetrated face which is closest to the particle). The value of sphcon must be less than or equal to the value of parameter NBCPOS, which is hard coded in MPEF3D (currently NBCPOS = 6).
LAGC

This keyword specifies that the contact forces due to impact and sliding will be computed implicitly by the Lagrange multipliers method. This enables the coupling with the permanent connections (relations, boundary conditions, etc.)
MBACON

This keyword specifies that the characteristics of multi-layer homogenised elements will be read from a BACON file (see page GBC_0165).
POST

This option of MBACON indicates that the rupture criteria will be evaluated in the multi-layer elements during the direct calculation. During post-treatment, this option allows to compute the maximum deformations (upper and lower "skin"), and also the deformations along the directions of strain gauges.
SAUV

The directives for saving and restart are described in Section "SR" (see page GBSR_0010 and following).
ADDF

Advection-diffusion computation. The Eulerian description is used, therefore the "EULE" keyword is compulsory in this case. See description on page GBA_0031.
NAVS

Solution of Navier-Stokes equations (for fluid velocities) has to be performed in the advection-diffusion computation. See description on page GBA_0031.
TEMP

Solution of the temperature equation has to be performed in the advection-diffusion computation. See description on page GBA_0031.
TURB

Solution of the turbulence equations (k, eps) has to be performed in the advection-diffusion computation (this option is still under development).
MECA

ALE computation with mechanical rezoning model.
MEDE

to create a med file. See description on page GBG_0070.
EROS

This keyword activates the “erosion” algorithm of the code. The algorithm has the following characteristics:
1- Those elements whose erosion criterion (mainly number of failed Gauss points where failure is triggered by damage, principal strain, minimum pressure, ...) is beyond a certain level are considered as eroded and are ignored during the rest of the calculation. Erosion can activated in general for all structural elements. The failure criterion of one Gauss point can be defined via a global command in COMP (page GBC_0069), or in some materials. Erosion can also be defined using displacement erosion (see GBC_0067) or using a minimum time step size of an element (see page GBI_0020).
2- In the case of a calculation with contact by sliding surfaces in 3D (see page GBD_0180), the contact surfaces are updated by eliminating the eroded elements.
3- The list of the eroded elements is stored in the results file. This allows to remove them from the visualization (if so desired) during the post-treatment.
4- The erosion can also be activated for a part of the elements (see page GBC_0069).
5- Obsolete are the keywords FAIL and GHOS.
ldam

Optional parameter indicating the number of failed Gauss points that cause erosion of the element, in proportion to the total number of Gauss points of an element. It should lie between 0 and 1. The default value is 1. Negative values indicate no erosion will taken into account for material erosion. The value 1.0 indicates that an element is eroded when all its Gauss points have failed. The value 0.5 indicates that an element is eroded whenever approximately half of its Gauss points have failed. The special value 0.0 may be used to indicate that an element is eroded when any one of its Gauss points fails. This value is global and is used (as a default) for all elements in the current calculation. However, specific material types (see e.g. LEM1) may contain parameters that allow to override this value. In this way the user may set different values of the erosion threshold in different parts of the model (e.g. low values or even 0.0 for very brittle materials such as glass, and high values for ductile materials such as metals).
CROI

This option allows the erosion of crossed elements (negative Jacobian matrix/negative volume). The calculation is not stopped in such case.
LIMI

Special limitation for the element erosion: 2D: only elements, which have not 3 nodes connected to already failed elements can fail. This avoids large zone with eroded elements.
SCLM

This keyword introduces options related to memory distribution in MPI calculations, see details on Page GBA_0037.
BMPI

The simulation will only be executed using a parallel MPI version of EUROPLEXUS. Any sequential version running the case will produce a clean stop just after the keyword is read, declaring any qualification as valid.
RISK

This keyword activates the calculation of risk analysis related to explosive events. Note that to perform this type of analysis, it is mandatory to use standard measurement units. In particular, the pressures must be expressed in Pa. This is because the model internally uses some non-dimensionless constants. Furthermore the model assumes that the atmospheric pressure has the standard value of 1.D5 Pa, i.e. 1 bar. The risk estimation is performed according to the two references listed below. In order to compute the total probability from the probit functions, two different approaches can be chosen using the keyword PROB. A very conservative probability function from Yet-Pole can be activated with YETP. The more realistic probability function of Ferradás can be chosen with FERR (this is the default in case no PROB is defined). Two different formulations for risk of lung haemorrhage can be activated using the keyword LUNG. The default is equation (7, Baker, BAKE) from Ferradas paper. Equation (9, Lees, LEES) doesn’t consider the impulse and is conservative. Note that thre optional sub-directives PROB ... and LUNG ... must be re-defined in case of results reading from an Alice file. This allows to perform a calculation, say, with the default values (i.e. by specifying only the RISK directive, possibly followed by SPLI if so desired), and then to do several post-processing of the results each time computing (and visualizing) the risk by using a different set of sub-options (e.g. once by using the Ferradas probits and another time using the Yet-Pole probits), without having to run again the main calculation (which may be very time-consuming). Therefore, be aware that in calculations with risk it is mandatory to re-define the entire RISK directive before the RESU directive (which typically reads the results from an Alice file).
SPLI

The risk of death is split into three contributions: i) risk of head impact; ii) risk of body impact and iii) risk of lung haemorrhage. The resulting risk can only be visualized starting from a PVTK results file.
ADAP MLVL

[MPI Only] Automatic dimensioning for ADAPTIVITY: rlvl is an estimated average refinement level for all the adaptable elements of the mesh (floating point value)). It is used to compute the size of the extension zones in replacement of the DIME ADAP directive. Specific values can also be entered for given element types through the rlel floating point parameter associated to one element name ’nomelm’.
CFVN

Create the central Finite Volume nodes in Cell-Centred Finite Volume meshes.

References

The “probit” functions for risk estimation are taken from:


Comments:


The CASTEM directive is meant to read data produced by CAST3M and saved by the directive "SAUV". It will read also objects of type ’champoint’ explicitly stored, together with the mesh, by CAST3M.


On the other hand, the GIBI directive is meant to read only mesh objects (maillage) produced by CAST3M and saved by the directive "SORT". No champoints may be stored by CAST3M with this directive, therefore they may not be transmitted to EUROPLEXUS.


The syntax in CAST3M is:


(SORT)


Assume we have an object 'mymesh' of type 'maillage' to write on the file 'myfile.msh' on the current directory. Then :


    . . .
    OPTI SORT 'myfile.msh' ;
    SORT mymesh ;
    . . .



(SAUV)


Assume we have an object 'mymesh' of type 'maillage' and an object 'mychampnt' of type 'champoin' to write on the file 'myfile.msh' on the current directory. Then :


(formatted mode)


    . . .
    OPTI SAUV FORM 'myfile.msh' ;
    SAUV FORM mymesh mychampnt ;


or:


(XDR mode)


    . . .
    OPTI SAUV  'myfile.msh' ;
    SAUV  mymesh mychampnt ;


or:


(binary mode)

    . . .
    OPTI SAUV BINA 'myfile.msh' ;
    SAUV BINA mymesh mychampnt ;


Note that, if the data have been produced by CAST3M in formatted mode, then the keyword FORM may optionally be used in the EUROPLEXUS directive, for clarity, but it is not necessary, since this is the default reading mode for this directive.


On the other hand, if the data have been produced by CASTEM in "XDR" (rep. "BINA") mode, then the keyword XDR (resp. BINA) is mandatory in the EUROPLEXUS directive.


Note also, the XDR mode is the default mode for CAST3M output "SAUVER" file.


In the case of the "GIBI" directive, the mesh file is always formatted.


If neither the keyword "GIBI" nor "CASTEM" appear, the program assumes that the mesh is directly given in the main input file under the form of a list of coordinate values, and as many lists of node index (topology) values as there are element zones. This format is also known as the ‘COCO’ type format.

This form allows also to use meshes issued from mesh generators other than CASTEM-GIBI or even, in case for example the mesh is quite simple, to enter this data directly, or to generate them by an independent software. For more information, consult the ’GEOM’ directive.


The type of problem directive must be specified and contain at least one keyword (at least 2 for non-Lagrangian cases), for example:


    "AXIS"


or

    "TRID"  "ALE"


The various options are mutually incompatible.


I-DEAS mesh


When the IDEA directive is used, the program reads the mesh from an I-DEAS ‘universal file’. This file may contain other information besides the mesh, but the extra information is ignored.


The program interprets the following information: 1) nodal coordinates (dataset 781 or 2411) ; 2) element topology (dataset 780 or 2412); 3) permanent groups (dataset 752 or 2429 or 2430). Permanent groups are identified by a name, which can then be used in the EUROPLEXUS input file (like in the case of CASTEM mesh) to identify the corresponding list of nodes or elements.


Note that normally I-DEAS universal files do not have consecutive node or element numbers, while EUROPLEXUS requires consecutive numbering (and starting from 1). In order to solve this problem, use the optional REWR directive: the code reads the universal file (use extension ‘.unv’), re-orders the mesh numbering and writes the result in a new universal file (same name but with the characters ’new’ appended). Nodes are re-ordered simply by eliminating ‘holes’ in the numbering. For the elements, however, a subdivision into homogeneous ‘blocks’ of the same element type, material and physical properties (geometrical complements) is performed. A summary of the resulting blocks is printed on the listing.


Elements are re-ordered subdividing them into homogeneous ‘blocks’ of the same element type, material and physical properties (geometrical complements). This permits the mapping of the I-DEAS element library onto the EUROPLEXUS one, for the relation between I-DEAS and EUROPLEXUS element libraries is not unique. The ordering criterion followed by the procedure is: [material property number] - [element type number] - [physical property number]; as an example, if some elements have to be declared as the last ones (i.e. CLxx elements when present), they must be associated to the highest material number in the I-DEAS mesh.


A list of the resulting blocks is printed on the listing, containing the number of elements, the element type in I-DEAS mesh and a list of possible choices for the corresponding EUROPLEXUS element type; these informations are useful in order to set up the declaration of the geometry in the EUROPLEXUS input file (see 5.3).


The MAPP optional directive may be used in order to stop the code right after writing the re-ordered universal file.


Example 1: EUROPLEXUS input file:

    $-------------------------------------
    Example of use of IDEAS universal file: 1. file re-writing
    IDEA 'myfile.unv' REWR MAPP
    DIME TERM
    FIN


This input reads in universal file ‘myfile.unv’, re-orders the mesh and produces a new universal file ‘myfile.unvnew’.


It is important to note that in order to post-process the EUROPLEXUS results with I-DEAS, use should be made of the reordered universal file (myfile.unvnew in the above example).


Example 2: EUROPLEXUS input file:

    $-------------------------------------
    Example of use of IDEAS universal file: 2. actual computation
    IDEA 'myfile.unvnew'
    DIME
    ...
    (problem definition, using 'permanent group' names)
    FIN


In this second example, the geometry is read from the re-ordered universal file, and in any successive input directive the names of permanent groups may be used to define element or node lists. The syntax is the same as with CAST3M objects.


MED mesh


When the MEDL directive is used, the program reads the mesh from a MED file. This file may contain other information besides the mesh. If the file comes from EPX or Code_Aster, displacements, velocities, strains, stresses and internal variables could be read and used for the initialization. (See description on page GBE_0180). Other extra informations are ignored.


From the elements families and from the nodes families the program reconstructs the elements groups and the nodes groups. Groups are identified by a name, which can then be used in the EUROPLEXUS input file (like in the case of CASTEM mesh) to identify the corresponding list of nodes or elements. The elements groups described in a MED file are homogeneous ‘blocks’ of the same geometric support.


Note that the MED elements numbers are not necessarily the EUROPLEXUS elements numbers.

A summary of the resulting blocks is printed on the listing.


Warning


For an axisymmetric computation, the program considers a sector of ONE RADIAN. Therefore, all the forces, added masses, etc. must be defined correspondingly.


This has to be taken into account in particular when defining the mass associated to a material point: the “true” mass shall be divided by 2π.


Example:


If the whole force is Ftot, the force to be introduced in EUROPLEXUS is:

Fplex = 
Ftot
.

4.4.1  MODELING OF ADVECTION-DIFFUSION PHENOMENA

A.31

EUROPLEXUS includes a module for the modeling of advection-diffusion phenomena. This module stems from the TRAFLU-2D and TRAFLU-3D codes developed at JRC Ispra in the late eighties [53, 54].

The module is activated by using elements of type ADQ4 (in 2D) or ADC8 (in 3D), the ADFM material, specific generalised “loads” (see page F.320) and initial conditions (see page E.85), and specific options (see page H.70). Here is a synthetic description of these models, borrowed from [54].

The model uses a quasi-explicit finite element algorithm for the solution of the basic equations describing combined conductive and convective transfer of heat in a liquid. The presence of enclosing solid (rigid) structures is accounted for.

The governing equations in the fluid region are the incompressible Navier-Stokes equations and the thermal energy equation. These equations are treated in an Eulerian frame of reference and they are expressed in terms of primitive variables: velocity, pressure and temperature.

The flow is assumed to be laminar and the fluid Newtonian and incompressible within the Boussinesq approximation. Either the velocity components or the total surface stress are specified as boundary conditions for the Navier-Stokes equations.

The governing equation in the solid is the transient heat conduction equation. Boundary conditions are of prescribed temperature, imposed normal heat flux and heat transfer by convection or radiation.

Spatial discretization is achieved by means of four-node quadrilateral elements in 2D (ADQ4) or eight-node hexahedral elements in 3D (ADC8) with multi-linear velocity and temperature fields. The pressure is assumed uniform over each fluid element.

A fractional step method is employed for time integration of the Navier-Stokes and thermal energy equations. This consists of three distinct steps dealing, respectively, with the advective terms, the viscous/diffusion terms and the pressure/incompressibility terms.

A second-order explicit Taylor-Galerkin method is used in the advection step, where the mass matrix is retained in its consistent form to improve phase accuracy.

A first-order explicit Euler method is used in the viscous-diffusion phase. Here the mass matrix is put into diagonal form.

Finally, a first-order implicit method is used in the pressure phase for the momentum equations. The pressure field itself is obtained as solution of a linear algebraic system arising from the discrete form of the incompressibility condition.

4.4.2  TYPE OF OUTPUT LISTING

A.35


Object:


To define the type of printed output listing. If nothing is specified, in extremely large model computations the standard listing could be very large. Therefore, it may be useful to selectively reduce the printed information via the following directives.


Syntax:

   < $ "LIST"

       | "COOR" ; "ELEM" ; "GIBI" ; "GRIL" ; "EPAI" ; "NORM" ; "NONE" |

       "TERM" $ >

COOR

the initial nodal coordinates will be printed on the output listing; furthermore, the principal directions of inertia of COQI element nodes will also be printed
ELEM

the mesh topology (element nodes) will be printed on the output listing
GIBI

the composition of CASTEM2000 objects will be printed on the output listing
GRIL

the characteristics of ALE grid motion will be printed on the output listing
EPAI

the initial element thicknesses will be printed on the output listing
NORM

the FSA and FSR normals will be printed on the output listing
NONE

none of the above quantities will be printed on the output listing

Remarks


By default, i.e. in the absence of the LIST directive, all the above quantities are printed out in the normal way. When the LIST directive is encountered, all the above printouts are inhibited, i.e. the effect is the same as with LIST NONE. Any of the keywords COOR ... NORM may then be used to re-activate the printing of selected quantities. In this case, however, printing of sequences of integer numbers occurs in a “compact” way, in the sense that any sequence of four or more consecutive numbers n1, n2, ..., nn is listed simply as ’n1 to nn’. In many cases this allows important savings in the quantity of output data.

For example, the directive:

  LIST NONE ELEM EPAI TERM

would print only the mesh topology and element thicknesses.


To obtain the most compact listing, use LIST NONE TERM.


Another way of obtaining a compact listing is the option OPTI NOPR, see Page H.50. However, that directive does not allow selective printout.

4.5  MPI GLOBAL OPTIONS

A.37


Object:


Optional global options to set for MPI calculations:


Syntax:

    < "SCLM" <"DTUN"> <"PMET"> <"ROB"> <"CINI">
             <"WFIL" <ndwfil>> <"DACT" /LECDDL/> <"DPRE" ipre>
             <"IOPT" iopt> >

    < "BMPI">


DTUN

Multiple time scales treatment (one per subdomain) is deactivated. Every subdomain has the same time scale (see comment below).
PMET

ParMetis library is used to perform domain decomposition.
ROB

Recursive Orthogonal Bisection algorithm is used to perform domain decomposition (see comment below).
CINI

Automatic domain decomposition with ROB after a restart is performed using initial coordinates instead of current coordinates.
WFIL

Use of an element weight file for automatic domain decomposition (see comment below).
ndwfil

Number of the logical unit of the weight file or file name in quotes. If omitted, the program chooses a file name by default (see page A.27). The default extension is .wgt.
DACT

Selection of active directions (from 1 to 2 in 2D, from 1 to 3 in 3D) for automatic domain decomposition using ROB.
ipre

Number of the first cutting direction for automatic domain decomposition using ROB (see comment below).
iopt

Level of memory optimization (see comment below).
BMPI

When present, the current dataset can only be run using MPI.

Comments:


Keywords to be used with SCLM option are very close to the ones dedicated to the STRUCTURE directive with automatic domain decomposition activated (keyword AUTO, see page I.15). Indeed, to provide an optimized memory distribution, the domain decomposition has to be defined and performed before the global data structure is built and initialized, which is not the case when using the STRUCTURE directive just before launching the calculation. Only automatic domain decomposition can be defined this way. See comments on page I.15 for a complete description of keywords DTUN, PMET, ROB, CINI, WFIL, DACT, DPRE.


When activating memory optimization for MPI calculations with SCLM option, the STRUCTURE directive must not be used, since domain decomposition has already been defined.


IOPT keyword is used to define the level of memory optimization: the more aggressive the optimization is, the more restrictions upon output and qualification there are.


TIP: The right way to deal with restrictions imposed by SCLM option is to write an ALICE file during the parallel calculation within a series of time-steps of interest and then to generate the desired output files and perform the desired qualifications from this file.

4.6  DIMENSIONING

A.40


Object:


Allocation of memory for the problem variables.


Syntax:
    "DIMENSION"



Comments:


The dimensioning of variables data is specified by keywords, which enable the user to reserve for a given problem only the memory that will be really necessary to perform the computation. All the dimensions are maximum values, their value by default is 0 (unless a different value is specified in the description).


On the following pages, the keywords have been classified according to the data they affect. Actually, they can be provided in any order. These keywords together form the directive "DIMENSION".

4.6.1  DIMENSIONS RELATIVE TO GROUP B (GEOMETRY)

A.50


These dimensions concern the geometry (elements) and, in ALE computations, the motion of grid nodes.


Overview:

The overall syntax is as follows:

    < NPOI np   >  < NDDL   nd >
    < "typ1" n1 "typ2" n2 ...  >

    < ADAP NPOI np <NIND ni> <NVFI nvfi> <NTHR nthr> <NPIN npin>
           "typ1" n1 "typ2" n2 ... ENDA >

    < DECO NPOI np ENDD >

    < NALE nale >  < NBLE nble >

    < NGPZ mxngpz >

    < ME1D me1d >

NODES

A.55


Syntax:

    < "NPOI" np  >  < "NDDL" nd >


np

Maximum number of mesh points. This parameter is not necessary, except some special cases. (Cf. comment below).
nd

Total number of degrees of freedom. This parameter is not necessary, except some special cases. (Cf. comment below).

Comments:


Normally EUROPLEXUS detects automatically the exact number of nodes (and the number of degrees of freedom), the exact number of each element types required, from the input file or from the associated mesh file. Therefore, the directives NPOI, NDDL and TYPi are usually not necessary.
These directives are needed only in special cases, whereby EUROPLEXUS has to create additional nodes (not specified in the input nor in the associated mesh file) after the reading of the geometry: for example a pipeline circuit with a bifurcation, a rigid body, or in case of remeshing.

NUMBER OF ELEMENTS

A.60


Object:


The number of the different elements that will be used in the problem is specified (if necessary).


Syntax:
    | "typ1" n1 "typ2" n2 .....  |


typi

name of an element type (see page INT.80).
ni

maximum total number of corresponding elements.

Comments:


Normally EUROPLEXUS detects automatically the exact number of each element type required, from the input file or from the associated mesh file. Therefore, theses directives are usually not necessary. These directives are needed only in special cases, whereby EUROPLEXUS has to create additional elements (not specified in the input nor in the associated mesh file) after the reading of the geometry: for example a pipeline circuit with a bifurcation, a rigid body, in case of remeshing, or in case of flying debris.


The various elements are described on page INT 80.


Warning :


If you use 1-D elements (except ED1D), the directives:

    "TRID"  "EULE"


are mandatory in the definition of the problem type (page A.30).

ADAPTIVITY (Adaptive Mesh Refinement)

A.62


Purpose:

This optional sub-directive allows to set the dimensions for the automatic mesh refinement during a computation, as required e.g. in adaptivity. The directive syntax is similar to that described in the previous pages for the “base” mesh. The user must define the maximum number of nodes, of degrees of freedom, and of elements (for each element type which can be refined) that are allowed to be “created” during the transient calculation. This is referred to as the “extension” zone as opposed to the “base” zone containing the base (normal) mesh. The optional directive must be terminated by the keyword ENDA.


Syntax:

    < ADAP
           NPOI np <NIND ni> <NVFI nvfi> <NTHR nthr> <NPIN npin>
           "typ1" n1 "typ2" n2 ...
      ENDA >


np

Maximum number of mesh points in the extension zone.
ni

Total number of error indicator variable types used in the adaptive calculation. For example, if one wants to use both displacement and velocity as indicators, then it must be NIND 2. By default (i.e. if this keyword is omitted) only one error indicator variable is allowed. This quantity is used only in adaptive calculations with the error indicator.
nvfi

Maximum number of cell-centred finite volume (VFCC) interfaces in the extension zone. This quantity is used only in adaptive calculations with VFCC fluids.
nthr

Total number of threshold indicator variable types used in the adaptive calculation. For example, if one wants to use both displacement and velocity as indicators, then it must be NTHR 2. By default (i.e. if this keyword is omitted) only one threshold indicator variable is allowed. This quantity is used only in adaptive calculations with the threshold indicator.
npin

Maximum number of parent (0-level) pinballs in the extension zone. Such pinballs are automatically created during the mesh refinement process if the element being split has an attached (parent) pinball (and this recursively).
n1, n2 ...

Total number of elements of type "typ1", "typ2" etc. in the extension zone. For the names of the element types see pages INT.80, INT.90 and INT.100.



Comments:

The number of degrees of freedom in the extension memory zone (i.e. the dofs relative to the adaptive nodes) is automatically computed by the code as the number of nodes in the extension zone (np) multiplied by the space dimension (2D or 3D). This implies of course that only elements whose nodes do not have any rotational dofs can be used in adaptivity, for the moment.

DECOHESION (Automatic Separation of the Elements)

A.63


Purpose:

This optional sub-directive allows to set the maximum number of created nodes during a computation as required for this numerical method (Automatic Separation of the Elements). Automatic separation of the elements is only available for CUB8 elements affected by the BOIS (wood) material. More explanations can be found in [840]. The optional directive must be terminated by the keyword ENDD.


Syntax:

    < DECO
           NPOI np
      ENDD >


np

Maximum number of created nodes during a computation.



Comments:

For the moment this method (Automatic Separation of the Elements) is only available for CUB8 elements affected by the BOIS (wood) material.

GRID MOTION (A.L.E.)

A.65


Syntax:

  < "NALE" nal  >  < "NBLE" nbl  >


nale

Maximum number of ALE nodes subjected to manual (i.e., non-automatic) rezoning. To be used only in ALE computations. The nodes are specified by the GRIL directive. By default (i.e., if not specified) the code assumes nale = 1 for ALE calculations.
nble

Maximum number of ALE nodes subjected to automatic rezoning. To be used only in ALE computations. The nodes are specified by the GRIL directive. By default (i.e., if not specified) the code assumes nble = 1, for ALE calculations.

SPACE INTEGRATION FOR SHELL AND BEAM ELEMENTS

A.66


Syntax:

  < "NGPZ" mxngpz  >


mxngpz

Maximum number of Gauss Points through the thickness for shell, plate or beam elements which are integrated through the thickness. This value overrides the default value set in INICO1 for each of these element types. This value is global and affects all the concerned element types. To set the “true” number of integration points through the thickness for each element (possibly a different value for each element), see the COMP directive (Geometrical Complements) on page C.42.

MEMORY FOR ED1D CALCULATIONS

A.67


Syntax:

  < "ME1D" mead  >


me1d

Length of memory table (in REAL*4) for the ED1D calculations, in case of a coupled 1-D/multi-D calculation. The 1-D part is computed by the EURDYN-1D code, now embedded in EUROPLEXUS (see Page I.23). The default value of me1d is 50,000.

4.6.2  DIMENSIONS RELATIVE TO GROUP C (MATERIALS)

A.70


Object :

Dimensions relative to the materials used.


Syntax :

    < "LMAS" lmas >
    < "ECRO" lecr >
    < "PYRO" mxpyro >
lmas

Size of the consistent mass matrix.
lecr

Maximum length of the vector of parameters associated to materials (ECR). This parameter is not necessary, except some special cases. (Cf. comment below).
mxpyro

Maximum number of distinct oil pyrolisis bubbles (material FLUT ... PYRO, see page C.530). This material is part of the models developed by the CESI team (formerly at ENEL, Milano) in collaboration with JRC.

Comments :

Normally EUROPLEXUS detects automatically the exact length of the ECR vector associated to materials, from the input file. Therefore, the directive ECRO is usually not necessary. This directive is needed only in special cases, whereby EUROPLEXUS has to create additional elements (not specified in the input nor in the associated mesh file) after the reading of the geometry: for example a pipeline circuit with a bifurcation, a rigid body, or in case of remeshing.


It is compulsory to enter the size of the consistent mass matrix, when the computation includes the material "MHOM".

4.6.3  DIMENSIONS RELATIVE TO GROUP D (CONNECTIONS)

A.80


Object:


Dimensions relative to the couplings.


Syntax:
    < "MXLI" maxlie >        < "LNOD" maxnod>    < "LCOF" maxcof >
    < "GLIS" nslid nemax >   < "JONC" njonc >
    < "NPEF" nmpef    "NPTS" nomax >             < "SOLI" nsol >
    < "MECA" nmeca >
    < "FSSA" mxfssa >      < "FSSL" mxfssl >      < "FSSF" mxfssf >
    < "NBJE" nbjeux >
    < "VCON" mxvcon >


maxlie

Total number of connections in the ’LIAISONS’. This parameter is not necessary, except some special cases. (see comment below).
maxnod

Total number of nodes involved in the ’LIAISONS’. This parameter is not necessary, except some special cases. (see comment below).
maxcof

Total number of coefficients used in the ’LIAISONS’. This parameter is not necessary, except some special cases. (see comment below).
nslid

Number of couples of sliding lines.
nemax

Total number of nodes defining these lines (master AND slave).
njonc

Total number of nodes involved in a "TUBM" or "TUYM" type of junction.
nmpef

Number of "particle-structure" couples.
nomax

Total number of nodes defining these "particle-structure" couples.
nsol

Number of rigid solids.
nmeca

Total number of mechanisms.
mxfssa

Maximum number of nodes or element side couples subjected to fluid-structure sliding of the ALE type according to JRC’s model (see directive "FSS" "ALE").

mxfssl

Maximum number of nodes or element side couples subjected to fluid-structure sliding of the Lagrangian type according to JRC’s model (see directive "FSS" "LAGR").

.

mxfssf

Maximum number of nodes or element side couples subjected to fluid-structure sliding of the fixed type according to JRC’s model (see directive "FSS" "FIXE").

nbjeux

Number of couples of nodes to which an impact with gap is associated.
mxvcon

Maximum total number of parameters used to define bilateral constraints (CONT SPHE, CYLI, CONE, TORE) with variable coefficients (OPTI CONT VARI). Each sphere requires 3 parameters, each cylinder or cone requires 6 parameters, and each torus requires 9 parameters).

Comment:


Normally EUROPLEXUS detects automatically the exact number of LIAISONS parameters required, from the input file. Therefore, the directives MXLI, LNOD, LCOF, ... are usually not necessary. These directives are needed only in special cases, whereby EUROPLEXUS has to create additional nodes or additional elements.

4.6.4  DIMENSIONS RELATIVE TO GROUP G (PRINTOUTS)

A.100


Object:


Dimensions relative to printout and storage keywords.


Syntax:
    < "MTTI" mttime >   < "MNTI" mntime >
    < "NFRO" nfront >   < "NPFR" npfron >
    < "NEPE" nepedi >


mttime

Maximum number of times for which the printing/storage of the results is requested.
mntime

Maximum number of time steps for which the printing/storage of the results is requested.
nfront

Number of borders (’frontiere’) for which the calculation of resultants is requested.
npfron

Total number of nodes involved (by putting all borders together).
nepedi

Length of the memory reserved for the vector NEPEDI which is constructed in subroutine edit1. The code normally computes this automatically.

4.6.5  DIMENSIONS RELATIVE TO GROUP I (CALCULATION)

A.105


Object:


Dimensions relative to the calculation run.


Syntax:
    < "TTHI" mtthis >


mtthis

Maximum number of time values for which the solution has to be computed, in case of "PAS UTIL" option and "CALC" ... "HIST" (the time marching is imposed by the user).

4.6.6  DIMENSIONS RELATIVE TO ADVECTION-DIFFUSION

A.110


Object:


Dimensions relative to advection-diffusion problems as declared by keyword "ADDF" above in this section.


Syntax:
    < "ELSN" mxelsn   "BWDT" mxbwdt   "TPOI" mxtpoi
      "ELGR" mxelgr   "CVEL" mxcvel   "GRPS" mxgrps >

mxelsn

Maximum number of elements surrounding (i.e., connected to) any given node.
mxbwdt

Maximum bandwidth of pressure matrix (for direct solution) or maximum number of elements surrounding an element (for iterative solution).
mxtpoi

Maximum number of time points for prescribed time-dependent ’charges’ in advection-diffusion problems (temperatures, heat flux, heat generation, heat convection, heat radiation, external pressure, velocities).
mxelgr

Maximum number of elements in each group with prescribed time-dependent ’charges’.
mxcvel

Maximum number of nodes with constrained velocities.
mxgrps

Maximum number of groups with prescribed time-dependent ’charges’.

4.6.7  END OF DIMENSIONING

A.200


Syntax:
      "TERM"



Comments:


The word "TERM" marks the end of the dimension, it must appear.


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