Automesh-2d User Manual

2.1.2 Remeshing. Remeshing or mesh re-generation needs two steps: (a) to extract the
boundary of the old mesh and generate new mesh; (b) to interpolate history field variables,
such as nodal temperature and elemental strain, from the old mesh to the new one.
In order to remesh, click on the button Read Mesh in the dialog and select the file that has the
old mesh information. A message box will appear. Choose YES to remesh and the old mesh and
history field variable will be input; choose NO only to read the mesh including nodal coordinates
and element connectivity.

In remeshing, you can set the parameters as you do in the initial mesh generation, but at
this time you can set the density weight of strain, strain rate and temperature distribution.
After all the parameters are set, click on the button Remesh to generate new mesh and
interpolate history field variable from old mesh to the new one.
To save the mesh to a file, click on the button Write Mesh in the dialog and input the file
name. The file is text format (the extension .msh). The detail formats of the file please
refer to the example file OLDMESH.MSH.

2.2 Used-defined density and mesh generation

If the user want to define density on the boundary and in the domain manually, click on the
button User-defined Density in the dialog and the dialog User-defined Mesh Density will
appear.

The user can designate the relative density value on the points of the boundary and internal
domain. The system will generate the density of smooth transition according to the density
points and then generate the mesh. The definition of density points is as following:

(1) The type of density point. There are two types of density points, i.e. boundary point and
internal point.

(2) The relative density value on the point. Enter the value in the edit box.

(3) Add a density point. Select the type, enter the coordinates and relative density value, and
click on the button Add to add a density point. You can also click on a point in the graphic area
to add a density point, since its position does not need to be very accurate.

(4) Modify a density point. Select the point from the list first, or select it in the graphic area by
the mouse. Select the type, enter new density value and coordinates and click on the button
Modify. You can also press the mouse button on the point and drag it to proper location.

(5) Delete a density point. First select the point, then click on the button Remove.

(6) Delete all the points. Click on the button Remove all, and all the density points will be
deleted.

After all the boundary and internal density points are defined, the only parameter needs to be
set is the number of elements to be generated. Click on the button Generate Mesh in the dialog
and the system will generate the mesh density according to use-defined density points and
then the mesh. Notice: if only internal density points are defined, the relative density on the
boundary is set 1 by the system. For example, in Fig. 5, five internal density points are defined
in the square, and all the relative density values are 3.

If the user want to keep boundary nodes as mesh nodes, please check the item Keep
boundary nodes in the dialog. Since the boundary nodes are generated, the absolute density
value on the boundary is determined. At this situation, only internal density points need to be
defined and the element size, not the relative density, needs to be entered. In order to
generate all-quadrilateral mesh, each boundary must have even number of nodes.

In the circumstance, the absolute density value is used, so the number of the elements to be
generated can be determined by the system. Just click on the button Generate Mesh in the
dialog, and the system will generate the density of smooth transition according the absolute
density value and the mesh.

The other parameters that are used in density generation and mesh generation are listed in
the dialog Mesh Control Parameters. Usually the parameter need not to be changed.