Builds a set nodes (logically rectangular) and creates finite element connectivity. This command is similar to the quadxyz command except that symmetry flags are included and elements are created.
The brick option specifies that a mesh is connected into elements. This command can be used to create finite element connectivity on a logically rectangular set of nodes created by another method. See quadxyz or createpts command without the brick option.
Make the mesh object with the cell type the brick makes, using cmo/create. For instance,
cmo/create/mo_name / / / hex or cmo/create/mo_name / / / quad.
The brick sets the cell type of the mesh object itself: hex (ni,nj,nk all greater than 1), quad (one of them 1) or line (ni,1,1). A mesh object with no cells yet, of any type (for instance one made with cmo/create/mo_name and no type, which is tet), becomes a hex, quad or line mesh object, and the result is the same as in a mesh object of that type. Adding a brick to a mesh object that already has cells of another type (tets, say, or hexes for a quad brick) is an ERROR: the two kinds of cells cannot share one mesh object.
createpts/brick / xyz or rtz or rtp / ni,nj,nk / xmin,ymin,zmin / xmax,ymax,zmax / iiz,ijz,ikz / [ iirat,ijrat,ikrat / xrz,yrz,zrz / isym,jsym,ksym ] createpts/brick / xyz or rtz or rtp/ ni,nj,nk / 1,0,0 / connect /
Note these actions apply to a hex or quad mesh object as defined with the create command or generated from another command.
xyz specifies Cartesian coordinates.
rtz specifies cylindrical coordinates.
rtp specifies spherical coordinates.
ni,nj,nk are the number of points to be created in each direction.
xmin,ymin,zmin are the minimums for coordinates.
xmax,ymax,zmax are the maximums for coordinates.
iiz,ijz,ikz if = 0 then mins and maxs are used as cell centers if =1 then mins and maxs are used as cell vertices. The default is 1,1,1
iirat,ijrat,ikrat are optional and set the ratio zoning switches (0=off,1=on)
xrz,yrz,zrz are optional and are the ratio zoning value - distance is multiplied by the value for each subsequent point.
isym,jsym,ksym are optional periodic (wrap-around) switches, default 0,0,0. They come after the ratio zoning tokens, so those must be given too, even if ratio zoning is off. With jsym = 1, the last layer of cells in the j direction is joined to the FIRST layer of vertices (j = 1) instead of the last (j = nj). isym does the same in i, and ksym in k. Use a switch only where the first and last vertices of that direction are at the same place, as in rtz with theta from 0 to 360 (jsym), or rtp with phi from 0 to 360 (ksym). The seam is then closed in the connectivity without filter. The vertices of the last layer (j = nj) are still created, but no cell uses them. In any other case the wrap makes cells that reach back across the whole mesh and overlap the others. For example, an xyz brick with isym = 1 reports a total volume larger than its box.
When a switch is used:
rtz brick still use several vertices at the same place on the axis. Only filter merges those;1,0,0 is the point set selection indicated by start,stride,stop or pset,get,pset_name where 1,0,0 are all points.
cmo/create/cmohex / / / hex
createpts/brick/xyz / 3,2,3 /0.,0.,0./1.,1.,1./1,1,1
Creates a set of hex points (3x2x3) and hex elements (2x1x2 hex) in the unit cube. The connect option should not be used in this case because the hex brick connectivity is created.
cmo/create/cmohex / / / hex
quadxyz /5,7,5/ 0.,0.,0./1.,0.,0./1.5,0.5,2.0/.5,.2,2.5/ &
-1.,1.5,0./2.0,0.,0.0/2.1,1.9,2.4/-0.2,1.8,2.3/
createpts/brick/xyz/5,7,5/1,0,0/connect
These commands create a 3D set of nodes using quadxyz and then creates hex connectivity with the createpts/brick command. Be careful that the nx, ny, nz values for both the quadxyz and createpts/brick command are the same.
cmo/create/cmoquad/ / / quad
quadxy/ 11, 11 / 0. 0. 0. / 1. 0. 0. / 1. 1. 0. / 0. 1. 0.
createpts/brick/xyz/11,11,1/1 0 0 / connect
The first line creates an empty quad cmo. The second line calls quadxy to create a 2D set of nodes. The last line uses createpts/brick to connect the points into quad elements.
define RTOP 20.
define NRADIAL 3
define NRAYS 20
define NRINGS 12
define WRADIUS 2.
define CIRDEG 360.
cmo/create/mo_cylinder / / / hex
createpts/brick/rtz/NRADIAL,NRAYS,NRINGS/0. 0. 0./ &
WRADIUS CIRDEG RTOP /1,1,1
Use the define commands to set variables for making a cylinder mesh.
This hex mesh has height of 20.
There are 3 points from center to rim, there are 20 points around and 12 points vertical.
Width of radius from center is 2 and the cylinder is a full 360 degrees.
cmo/create/mo_cyl / / / hex
createpts/brick/rtz/5,17,5/0.,0.,0./2.,360.,2./1,1,1/0,0,0/1.,1.,1./0,1,0
The same kind of cylinder, with jsym = 1: the cells from 337.5 to 360 degrees are joined to the vertices at 0 degrees, so the seam is closed without filter. The 25 vertices at 360 degrees (5 radii x 5 heights) are left unused. The ratio zoning tokens 0,0,0 / 1.,1.,1. (off) are needed to reach the switches.
LaGriT reads only the first 80 characters of an input line. A line that reaches the symmetry switches is easily longer than that, and then the switches are silently lost. Write such a command without spaces, as above, or continue it on the next line with &.