***mesh#

Description#

As introduced before, this command indicates the start of a new mesh object. The meshing operations which follow will act on the mesh object, until the next ***-level command is reached. At that point the mesh will be saved with the given name. Use of this command invariably involves use of the **open or **import commands.

Syntax#

The basic ***mesh section syntax is summarized below:

***mesh [ output-name ] \(~\,\) **export format  output-name \(~\,\) **open input-name \(~\,\) **open_mast mast-file.mast \(~\,\) **import format  input-name \(~\,\) **inp_file \(~\,\) **output output-name \(~\,\) **dont_save_final_mesh \(~\,\) **transform \(~\,~\,\) ...

The mesh output name output-name is the problem name, and therefore does not have the .geof suffix. It is optionally included on the same line as ***mesh for convenience.

**export

Write an input file in a format other than native Z-set.

**import

Open a mesh file in a format other than the native Z-set .geof format. The format type is a keyword for one of the external mesh formats allowed.

**inp_file

specify that the input file (FEA loads, BCs element formulation, time sequences, etc) are to be read and output with the mesh. This is probably desired in order to get as full an import or export as possible. Note: this command is provided as a convenience feature, and does not imply full compatibility between formats. It is likely the different codes options just do not have an equivalent for translation, and will be passed silently. Be careful as well not to overwrite existing hand-edited input files! – there are no questions before output is written.

**open

Open a file defining the mesh which will be operated on. There must be only one instance of open in the ***mesh block. The file name is the problem name without the .geof suffix. Additional mesh components can be loaded using **union command.

Note

After some transformations, one can save the current mesh using **save and reopen the original mesh using **reopen geom_file.

**open_mast

Open a Zmaster .mast file, running Zmaster batch on it beforehand. This open mode actually does a union, but normally it would be used in place of an **open or **import command.

**output

specify the output file.

**dont_save_final_mesh

disables writing the mesh, as it normally is the final stage of the meshing process.

Aside from the basic control options, any number of mesh transformation operations can be added in this section as indicated by **transform. The syntax and operation of these different mesher transformations are the subject of the remainder of this chapter.

Translations#

The following import/export translators are provided:

abaqus

Import/export an ABAQUS mesh and input file.

ansys

Exports mesh and input file commands to ANSYS input file.

gfm

Import/export the GFM format from COSMOS/M with input file commands.

gmsh

Import/export GMSH format. Only GMSH format’s version 2 is supported for export.

ideas

Import I-deas unv format.

k

Imports/exports to LS-Dyna input file.

neu

Import FEMAP neutral format.

mesh

Import Medit/Distene mesh format.

may

Import FORGE mesh format.

fg3

Import mesh from FORGE result file.

in3

Import mesh from REM3D result file.

th3

Import mesh from THERCAST result file.

These import functions currently only import geometrical information. Boundary conditions and real constants are mapped into mesh sets (nset, elset, etc) and given names based on their values.

Example#

A small example input follows. See the following sections for more examples demonstrating the individual operations. This example opens up a sub-mesh named BASE1, rotates and flips it, and creates some node/boundary sets for it.

****mesher
 ***mesh BASE
   **open BASE1
   **rotate
     x1 1.  0. 0.
     x3 0.  1. 0.
   **switch *axis  -z z
   **rotate  x3 0. 0. 1. x1 0.984808 -0.173648 0.0
   **translate 0. -5.5 -1.0
   **nset base_fix *plane 0. 0. 1. 0.0
   **bset base_top *plane 0. 0. 1. 1.0
****return

Example#

Two examples follow, the first of mesh import and the second of problem export (mesh and loads).

****mesher
***mesh linear_trial              % start making file linear_trial.geof
  **import gfm big_mesh.gfm       % import a Cosmos/M model
  **quad_to_lin                   % linearize the mesh
  **elset front  *func x>0.0;     % generate new sets
  **elset bottom *func y<0.0;
  **renumbering frontal_only      % frontal renumbering
****return

****mesher
 ***mesh                          % no name because we're giving output
  **export abaqus abaqus_lin.inp  % via the export command.. abaqus format
  **inp_file                      % include info from the .inp file (BCs)
  **open zebu_lin.geof            % This specifies the input name for both
****return                        % the geof and .inp files