Correct meshing of plate elements is important in order to achieve accurate analysis results.
The main requirements are as follows:
The meshing tools currently available in SPACE GASS are summarized below.
Meshing terms
A number of terms used in the following discussion are explained as follows.
"Openings" are voids in the shape of circles, rectangles, squares or any other general polygon.
"Hard lines" are lines in a meshed panel that must be maintained when the mesh is created. For example, if a slab is supported by an internal wall then the nodes along the top of the wall that connect to the slab would form a hard line that must stay in place as part of the slab's plate mesh.
"Hard nodes" are similar to hard lines except that they are just single nodes. They could typically occur at the ends of internal columns that connect to a slab.
"Sub-panels" are panels within a main panel that could be in the shape of circles, rectangles, squares or any other general polygon. They could be used to model regions with a different thickness, offset or material to the main panel, such as you could get with a drop panel in a slab for example.
Advanced meshing tools
These are the new meshing tools that let you create a well conditioned plate mesh that could contain openings, hard lines, hard nodes and sub-panels.
Generate plate mesh from members
This is an advanced meshing tool that lets you draw members to define a panel, including openings, hard lines, hard nodes and sub-panels, and then convert it into a fully meshed plate panel. Once you have converted the members into the plate mesh you could delete the members if they are no longer required.
This is also an advanced meshing tool that lets you create a fully meshed plate panel by drawing it directly rather than by converting from members. It also lets you define openings, hard lines, hard nodes and sub-panels. Because it doesn't make use of the normal drawing alignment tools in SPACE GASS, you need to create nodes at the key points first and then attach to them while drawing the panel. For this reason, it is sometimes easier to use the "Generate plate mesh from members" tool described above.
This is an advanced version of the original mesh tool. Typically you would draw large quad or triangular elements using the "Draw" tool and then mesh them down to a well conditioned plate mesh using this mesh tool. It can also be used to refine an existing plate mesh or specific parts of it. Note that this tool replaces the plate elements being meshed and so any pressure or thermal loads previously applied to them will be deleted. It is therefore recommended that you finalise the use of this tool before you apply your plate loads in order to avoid having to re-apply them.
This is a mesh refinement tool that lets you select part of an existing mesh and then progressively refine or enlarge the selected elements with the simple click of a button. Note that this tool replaces the plate elements being re-meshed and so any pressure or thermal loads previously applied to them will be deleted. It is therefore recommended that you finalise the use of this tool before you apply your plate loads in order to avoid having to re-apply them.
Basic (legacy) meshing tools
This is the original mesh tool in SPACE GASS that generates a basic mesh made from uniform size quad or triangular elements. It may not be the best option to use if you want a mesh that has a mixture of coarse and refined elements.
This is a basic mesh refinement tool that splits the selected elements in half and maintains compatibility with the surrounding elements. It may not be the best option to use if you want a mesh that has a mixture of coarse and refined elements.
Other mesh related tools
This tool lets you merge triangular elements into quads wherever possible for a more efficient mesh.
If your plate panel is supported on soil you can use this tool to generate spring supports that model the elasticity of the soil based on the tributary area of each node in the panel. The tool also generates a compression-only member above each spring support so that uplift can occur.
This tool generates pattern loading on a plate panel for all combinations of alternate and adjacent spans in both the longitudinal and transverse directions.
Importing a meshed model from an STL file
SPACE GASS comes with an STL import facility that allows you to generate the complex models in other programs such as Trimble Sketchup or Microsoft 3D Builder and then import them into SPACE GASS fully meshed. The following model is an example of a beam that was generated in Sketchup and then imported into SPACE GASS and meshed. For further information on STL files, refer to "Importing STL files".
