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IntelliMESH - General

SLABS 3.5 software offers two alternative meshing algorithms:

-Mesh 2000 (the old mesh)

-Intelli MESH (introduced in v3.5)

Mesh 2000 is the original SLABS meshing algorithm. Mesh 2000 is a very basic but robust meshing algorithm, which requires the user to place the beams and walls only along slab panel edges, and columns at the slab panel corners. These rules are rather limiting, time consuming and generally results in larger models. Mesh 2000 requires the floor slab to be subdivided in a larger number of slab panels. However, they prevent many modelling mistakes.

IntelliMESH is using a much superior algorithm, which allows beams, columns and walls to be placed anywhere inside the slab panels. With this approach, fewer slab panels are required, and larger areas of the floor with uniform thickness and pressure load can be modelled as one slab panel. Beams, walls and columns can also be placed along slab edges.

IntelliMESH will place one node at each of the column centroids, and a minimum of two nodes on each wall, one node on each wall end. Depending on the mesh size, the software will subdivide the slab panel areas into smaller triangles, and it will place additional nodes along slab edges, walls and beams (see figure below).

The mesh size is controlled by the "Mesh Sub-Division" value available on the meshing input panel. A value between 0.5m to 1.5m will provide a finite element mesh of acceptable accuracy.

Any old data files generated with Mesh 2000 will work with both meshing algorithms.

IntelliMESH will identify a pair of closely spaced nodes, and report an error. This normally indicates a modelling error which has to be corrected. Very often there are slight overlapping slab panels which will cause this problem. All Close Node errors have to be eliminated before proceeding any further with the analysis, and a quick visual examination of the mesh is recommended.

The new IntelliMESH algorithm is identical to the meshing in R/C BUILDING and PT3D. This will guarantee easy file transfer between SLABS, R/C BUILDING and PT3D software.

Now SLABS can accept a floor directly from R/C BUILDING that can be ran without any modifications.

 

IntelliMESH - Editing Features

Originally, SLABS software had very restrictive editing features, i.e. the column can be place only at the slab panel corners, and the walls and the beams could be generated only along slab panel edges form one slab corner to another. These restrictions are more suitable for beginners, because the software itself will prevent any common modelling errors, and an inexperienced user can produce reliable models easier. However, this approach is rather tedious and more time consuming.

In SLABS 3.5 there is a switch to "relax" these limitations, which allow generation of the floor geometry in a "free" manner, which is more suitable for the IntelliMESH. On the "Settings" input panel, (bottom left corner) there is a switch "Intelli MESH Editing Rules", which will allow the user to place the columns, walls and beams anywhere inside slab panels. This approach is much faster, but it is much easier to make modelling mistakes. The IntelliMESH Editing Rules are suitable for more experienced users.

By using the IntelliMESH Editing Rules the columns, walls and beams can be created first, and then the slab panels can be introduced later using the walls and columns as reference points. The slab panels should be made as large as possible as the floor slab can be subdivided with very few slab panels. A slab panel is needed to accommodate the geometry, different thickness and different pressure.

All previous editing rules also work in IntelliMESH, i.e. the columns can still be positioned at the slab corners. All SLABS models created with earlier version of SLABS will work with IntelliMESH.

IntelliMESH Editing Rules allows defining new beams at a later stage at any location without modifying the slab panels. This is very a fast way to examine alternative designs and easily change the location of the beams.

 

IntelliMESH - DXF File Import

There is a new DXF import facility. The new DXF import feature can open a DXF file R12 or lower, and then columns, wall, line loads and slab panels can be selected individually or in groups and imported straight into the model. This operation can be repeated many times.

Usually, the CAD files are in mm, but SLABS software works in m. At import all CAD dimensions will be multiplied by a user selectable scaling factor. The default value is 0.001 (see figure above).

Columns must be provided in the CAD package as closed polygons or polylines. If the columns are drawn as line segments, they have to be re-drawn in the CAD package as polygons and then imported into SLABS.

Walls and Line Loads must be prepared as polylines or polygons. At import, each segment of the polyline will be converted into a wall. The CAD file needs to be prepared by introducing a polyline along the centre line of the walls. A CAD file may contain several polylines representing the walls or columns.