At the start of the calculations, this record is used to generate element_group records. Each element, all of whose nodes are part of the geometry_item, will get an element_group record with value element_group. Please realise that the geometry entity can be a two-dimensional area, a volume, etc.
This option comes handy whenever a part of the domain gets some specific element data. By example, this would be the case if different areas in the structure have different material properties like stiffness, etc.
Beware: any directly specified element_group records will be overwritten.
We show here two ways to get different element data in different regions: Both ways give elements with young 1.2 from x=0 to x=1, and elements with young 3.3 from x=1 to x=2.
First way:
..
node 1 0.
node 2 1.
node 3 2.
element 1 -bar2 1 2
element 2 -bar2 2 3
element_group 1 0
element_group 2 1
..
group_type 0 -materi
group_materi_elasti_young 0 1.2
group_type 1 -materi
group_materi_elasti_young 1 3.3
..
control_mesh_refine_globally 10 -h_refinement
..
Second way:
..
node 1 0.
node 2 1.
node 3 2.
element 1 -bar2 1 2
element 2 -bar2 2 3
..
group_type 0 -materi
group_materi_elasti_young 0 1.2
group_type 1 -materi
group_materi_elasti_young 1 3.3
..
geometry_line 1 0. 1. 1.e-4
geometry_line 2 1. 2. 1.e-4
area_element_group 1 -geometry_line 1 0
area_element_group 2 -geometry_line 2 1
..
See also area_element_group_method, area_element_group_sequence_elementgroup etc.