zone import command

Syntax

zone import s <s2 >keyword

Primary keywords:

use-given-ids    format

Import a grid from a file. The file named s is imported. A path can be part of the file name. If no extension is specified, .f3grid is assumed in FLAC3D and .f2grid is assumed in FLAC2D.

In FLAC3D, three formats are currently supported: FLAC native ( *.f3grid ), ANSYS ( *.lis ), ABAQUS ( *.inp ), and MIDAS ( *.csv ). The format will be automatically determined by the filename extension, but can be overridden with the format keyword.

In FLAC2D, only the native FLAC format ( *.f2grid ) is supported. The format keyword is disabled.

The command creates a new grid point for every gridpoint specified in the input file. Checking for duplicate gridpoints is not done. It is up to the user to merge imported grids with existing geometry. Warning messages are output if zones are degenerate or cannot support two overlays.

The following keywords are available:

use-given-ids

Force FLAC to use the same gridpoint and zone IDs as are specified in the import file.

format keyword (3D ONLY)

Specify the expected format of the input file, overriding any default decision made by checking the file extension. The following format types are available.

flac3d

Specify the native FLAC3D ASCII- or binary-format grid file, with an expected extension of f3grid. The binary-format grid file is usually with smaller size and imported quicker than the ASCII-format grid file. The details of ASCII-format of FLAC grid file is given below.

ansys

Specify ANSYS compatible mesh files, with an expected extension of lis. Note that the ANSYS format enabled here generally requires two different files, both with the same extension. The first file is assumed to contain the node/gridpoint information, and the second the element/zone information. Use “nlist” command in ANSYS to output nodes (gridpoints) to a file; and use “elist” command in ANSYS to output elements (zones) into another file. Any ANSYS element with more than 8 nodes is not supported.

abaqus

Specify an ABAQUS compatible mesh file, with an expected extension of inp. Acceptable ABAQUS elements are “c3d4”, “c3d5”, “c3d6”, and “c3d8”. Other ABAQUS elements are not supported.

midas

Specify MIDAS compatible mesh files, which should be exported from MIDAS into Excel files with an expected extension of csv. Note that the MIDAS format enabled here generally requires two different files, both with the same extension. The first file is assumed to contain the node/gridpoint information, and the second the element/zone information. Only 1-order element types, e.g., tetrahedron, pentahedron(pyramid), hexahedron) are supported. Each line of the nodes information file should starts with node ID and ends with three components of node coordinates. Each line of the element information file should starts with element ID, element type (tetrahedron, pentahedron, or hexahedron), and group name/ID, and ends with node ID list.

FLAC grid format specification

A FLAC ASCII-format grid file has the following specifications: comment lines start with an asterisk; blank lines are ignored; and comma separators between numeric values are optional.

A line starting with “G” indicates a gridpoint definition. A gridpoint contains an integer identifier (ID number) followed by the \(x-, y-\)coordinates (2D) or \(x-, y-, z-\)coordinates (3D) of the gridpoint (floating point numbers).

A line starting with “Z” indicates a zone definition. A zone contains a zone type identifier, an integer zone identifier, and the identifiers of the gridpoints comprising this zone.

The ID numbers for the gridpoints and zones must be positive integers. The ID numbers do not have to be sequential or consecutive (gaps are allowed in the numbering). However, every gridpoint ID referred to by a zone must exist in the gridpoint list somewhere. If the use-given-ids keyword is given, the ID numbers of gridpoints and zones specified in the *.f3grid or *.f2grid file are used in the final grid. Otherwise, gridpoints and zones are generated using the next available ID numbers (the default). Also, the use-given-ids keyword allows grids to be imported in a piecemeal fashion. For example, if you have the following grid files:

g1.f3grid – gridpoint definitions

g2.f3grid – more gridpoint definitions

g3.f3grid – more gridpoint definitions

z13.f3grid – zone definitions using gridpoint IDs from g1 and g3

z12.f3grid – zone definitions using gridpoint IDs from g1 and g2

groups.f3grid – groups into which zones fall

they can be imported as follows:

zone import 'g1.f3grid' use-given-ids

zone import 'g3.f3grid' use-given-ids

zone import 'z13.f3grid' use-given-ids

zone import 'g2.f3grid' use-given-ids

zone import 'z12.f3grid' use-given-ids

zone import 'groups.f3grid' use-given-ids

The only requirement for successful import is the gridpoints must exist prior to creating the zones that require them. Also, zones must exist prior to placing them in groups.

The following zone type identifiers are recognized:

B8 – brick type zone (3D ONLY)

W6 – wedge type zone (3D ONLY)

P5 – pyramid type zone (3D ONLY)

B7 – degenerate brick type zone (3D ONLY)

T4 – tetrahedral type zone (3D ONLY)

Q4 - quadrilateral type zone (2D ONLY)

T3 - triangular type zone (2D ONLY)

For the zone definition, the gridpoint ID numbers must be specified in the standard FLAC ordering (see Orientation of Nodes and Faces within a Zone). The redundant points for zones—such as wedge, pyramid, degenerate brick—are not specified in the grid file. For a B8 zone, 8 gridpoints must be specified, for a W6 zone, 6 gridpoints must be specified, etc.

A line starting with “ZGROUP” indicates a group definition for zones. The text immediately following the word ZGROUP is the name of the group. Following the group name, all zones belonging to this group are specified with zone ID numbers. A line starting with “F” indicates a face definition. A face line contains a type identifier (a unique identifier for the face) and a set of gridpoint IDs that form a face in a zone. In FLAC3D, type face identifiers are defined as “T3” for tetrahedral zone faces and “Q4” for quadrilateral zone faces. In FLAC2D, the type face identifier is “E2” for edges. Note that in 2D, all “faces” manifest as edges (lines).

A line starting with “FGROUP” indicates a group of faces. Face groups are used in the range logic, allowing the user to apply properties, boundary conditions, velocities, etc. to a set of faces. The face group line contains the face group name. Lines containing the identifiers of the previously defined faces will follow the FGROUP line. The face identifiers are separated by spaces. This will assign the group name to all faces in the line when the grid is created.

The code blocks below shows a portion of a FLAC3D and a FLAC2D grid file.

*FLAC3D input deck produced by KUBRIX version 7.1.0
*mesh built: Wed Nov 19 20:54:43 2003
*GRIDPOINTS
G 1, -6.133336e+000, -6.144340e+000, -3.999275e+001
G 2, -4.732805e+000, -7.033142e+000, -3.999276e+001
G 3, -2.777756e+000, -4.116792e+000, -3.999988e+001
G 4, -3.535428e+000, -3.535424e+000, -3.999989e+001
G 457, -2.745877e+000, -4.129570e+000, -3.201193e+001
                     .
                     .
                     .
G 6, -3.512750e+000, -3.501916e+000, -3.200895e+001
G 17, -8.901190e+000, -8.922812e+000, -3.999268e+001
G 8, -6.845476e+000, -1.015358e+001, -3.999268e+001
*ZONES
Z B8 1, 1, 2, 4, 1443, 3, 6, 1444, 5
Z B8 2, 7, 8, 1, 1445, 2, 1443, 1446, 1444
Z B8 3, 9, 10, 7, 1447, 8, 1445, 1448, 1446
Z B8 4, 11, 12, 9, 1449, 10, 1447, 1450, 1448
                     .
                     .
                     .
Z B8 2785, 13, 14, 11, 1451, 12, 1449, 1452, 1450
Z B8 62, 15, 16, 13, 1453, 14, 1451, 1454, 1452
Z B8 78, 17, 18, 15, 1455, 16, 1453, 1456, 1454
*GROUPS
ZGROUP ’granite type 1’
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
ZGROUP ’ore zone’
1601 1602 1603 1604 1605 1606 1607 1608

* FLAC2D grid produced by FLAC2D 9.00 Alpha 148
* Mon Feb 28 13:17:43 2022
* GRIDPOINTS

G 1, 3.87E+00,2.00E+00
G 2, 3.33E+00,0.00E+00
G 3, 6.42E+00,3.37E+00
G 4, 6.67E+00,0.00E+00
              .
              .
              .
*ZONES
Z Q4 1, 1, 2, 3, 4
Z Q4 2, 5, 6, 7, 8
Z Q4 3, 9, 10, 11, 12
Z Q4 4, 13, 3, 14, 15
              .
              .
              .

*GROUPS
ZGROUP "inner" SLOT "Construction"
10 5 4 7 6 1 17 3 16 2 13 12 15 14 9 8 11

Usage Example

The following examples illustrate how zone import can be used to import a grid from FLAC3D or a third-party tool.

To view this project in FLAC3D, use the menu command Help ► Examples…. Choose “UsersGuide/ProblemSolving/GridImport” and select “GridImport.prj” to load.

Import a grid from ABAQUS, e.g., mesh_abaqus.dat:

model new
zone import 'manifoldgasket_mesh.inp' format abaqus

Import a grid from ANSYS, e.g., mesh_ansys.dat:

model new
zone import 'NLIST.lis' 'ELIST.lis' format ansys

Import a grid from MIDAS, e.g., mesh_midas.dat:

model new
zone import 'nodes_midas.csv' 'elements_midas.csv' format midas