With this record and the control_mesh_macro_parameters record you define a macro region. The macro region will automatically be divided into finite elements.
The type of macro region is defined by macro_item. You can set macro_item to a -sphere (3D), -cylinder_hollow (3D), -brick (3D), -rectangle (2D), -circle (2D), -circle_hollow (2D) and -bar (1D).
The element type to be generated needs to be specified in element_name; only the elements -bar2, -tria3, -quad4, -tet4 and -hex8 can be generated.
The elements to be generated will get element_group element_group.
With attach_method you define how the new generated elements are attached to already existing directly neighboring elements. Setting attach_method to -tyings causes the new elements to be tied (equal displacements and, if present, equal temperatures) to the old elements. Setting attach_method to -nothing means that no special attachment conditions are needed (loose structures). To have contact conditions between the old and new elements, you need to specify contact data yourself.
With n ... you define how much nodes and elements will be generated. For a -sphere, first 8 elements are generated; you need to specify the number of refinements. For a -cylinder_hollow, you need to specify the number of nodes in the length direction, the number of nodes over the wall thickness, the number of nodes in circ. direction. For a -brick, you need to specify the number of nodes in length direction, the number of nodes in width direction and the number of nodes in height direction. For a -circle, you need to specify the number of nodes in a cross-section direction. For a -circle_hollow, you need to specify the number of nodes over the wall thickness, the number of nodes in circ. direction. For a -rectangle, you need to specify the number of nodes in width direction and the number of nodes in thickness direction. For a -bar, you need to specify the number of nodes.
Nodes on the boundary edge of the macro region automatically get a node_boundary record.
In the next example a tunnel of radius 1 is build. A lining of thickness 0.02 is used.
...
number_of_space_dimension 2
...
end_initia
...
geometry_point 1 0. 0. 1.
...
(apply initial load)
...
...
(create tunnel)
control_mesh_delete_geometry 10 -geometry_point 1
control_mesh_macro 20 -cylinder_hollow -tyings 6 12
control_mesh_macro_parameters 20 0. 0. 0.99 0.02 0. 360.
...
...
(study tunnel deformations in time)
control_timestep 30 ...
...
In the following example a sphere is generated, after which the nodes get an initial velocity:
...
number_of_space_dimension 2
...
end_initia
...
control_mesh_macro 20 -sphere ...
control_mesh_macro_parameters 20 ...
...
control_data_put 30 -node_dof -all
control_data_put_double 30 0. 1. ...
...