3.1.16. block Commands

The block commands generate regular meshes of quadrilateral or brick elements from a block of corner (and optional midside) node coordinates.

3.1.16.1. block2D Command

Generates a mesh of quadrilateral elements in 2D or 3D. In 3D models, a 2D surface mesh suitable for shell analysis is created.

block2D $numX $numY $startNode $startEle $eleType $eleArgs { $coords }

Argument	Type	Description
$numX	integer	number of elements in the local x direction
$numY	integer	number of elements in the local y direction
$startNode	integer	starting node tag for mesh generation
$startEle	integer	starting element tag for mesh generation
$eleType	string	quadrilateral element type (for example quad, ShellMITC4, bbarQuad, enhancedQuad)
$eleArgs	list	arguments required by the chosen element type
$coords	list	block corner coordinates in braces; nodes 1–4 are required, nodes 5–9 are optional for curved meshes

Only the first four corner nodes are required. Optional nodes 5–9 refine curved block geometries.

3.1.16.2. block3D Command

Generates a mesh of eight-node brick solid elements.

block3D $numX $numY $numZ $startNode $startEle $eleType $eleArgs { $coords }

Argument	Type	Description
$numX	integer	number of elements in the local x direction
$numY	integer	number of elements in the local y direction
$numZ	integer	number of elements in the local z direction
$startNode	integer	starting node tag for mesh generation
$startEle	integer	starting element tag for mesh generation
$eleType	string	brick element type (for example stdBrick, bbarBrick, Brick20N)
$eleArgs	list	arguments required by the chosen element type
$coords	list	block corner coordinates in braces; nodes 1–8 are required, nodes 9–27 are optional for curved meshes

Note

1. Variable substitutions are recognized when command arguments are placed in quotes.

2. In Tcl, corner coordinates are wrapped in braces. In OpenSeesPy, pass *eleArgs and *crds as separate positional arguments (no braces).

Example

1. Tcl Code

block2D 16 4 1 1 quad "1 PlaneStrain2D 1" {
   1 0 0
   2 40 0
   3 40 10
   4 0 10
}

2. Python Code

block2D(16, 4, 1, 1, 'quad', '1', 'PlaneStrain2D', '1',
        1, 0, 0, 2, 40, 0, 3, 40, 10, 4, 0, 10)

Code Developed by: fmk