Model.min_size_node_movement#

Model.min_size_node_movement(collection)#

Moves nodes along feature edges in a shell mesh to solve minimum element size failures. The mesh topology is not modified. The minimum element size is given by “Min Size” ( fail ) in the criteria file settings. The node movement is restricted to be along existing surfaces. The function expects that the criteria and parameter files are set. It honors the following fields from the parameter file to specify the maximum allowable node movement distance:

  1. Move across shared edges

  2. Move across free edges

  3. Move across non-manifold edges

Feature edges are constructed as:

  1. A set of 1D elements along FE edges

  2. If no 1D element is present in the model, using the feature angle given in the parameter file

  3. Node - geometry association

Node - geometry association is maintained after feature node are moved, however, free edge nodes may move tangential away from the surface and lose association.

Feature node movement is attempted in decreasing order of priority for:

  1. Internal low curvature shared edges

  2. Internal high curvature edges

  3. Free edges

  4. Non-manifold edges

Node movement is also part of the rebuild_mesh() function.

Parameters:

collection (Collection) – The collection containing the element entities to correct.

Example#

Move feature nodes of selected shell elements with 5 mm criteria and parameter file settings#
import hm
import hm.entities as ent

model = hm.Model()

model.setqualitycriteria(
    string_array=[
        " 0 penalty value      0.00    0.00    0.80    1.00   10.00",
        " 1 min length        1 1.0   3.000   2.749   1.502   1.000   0.749  1",
        " 2 max length        1 1.0   3.000   3.600   4.500   6.000   9.000  0",
        " 3 aspect ratio      1 1.0   1.000   2.000   4.400   5.000  10.000  0",
        " 4 warpage           1 1.0   0.000   5.000  13.000  15.000  30.000  0",
        " 5 max angle quad    1 1.0  90.000 110.000 134.000 140.000 160.000  0",
        " 6 min angle quad    1 1.0  90.000  70.000  46.000  40.000  20.000  0",
        " 7 max angle tria    1 1.0  60.000  80.000 112.000 120.000 150.000  0",
        " 8 min angle tria    1 1.0  60.000  50.000  34.000  30.000  15.000  0",
        " 9 skew              1 1.0   0.000  10.000  34.000  40.000  70.000  0",
        "10 jacobian          1 1.0   1.000   0.900   0.700   0.600   0.300  0",
        "11 chordal dev       0 1.0   0.000   0.300   0.800   1.000   2.000  0",
        "12 taper             1 1.0   0.000   0.200   0.500   0.600   0.900  0",
        "13 % of trias        1 1.0   0.000   6.000  10.000  15.000  20.000  0",
    ],
    mode=0,
)

model.elementchecksettings(
    solver=-1,
    jacobian_2d=0,
    jacobian_3d=0,
    min_len_2d=2,
    min_len_3d=1,
    aspect_2d=0,
    aspect_3d=0,
    skew_2d=0,
    skew_3d=0,
    angle=0,
    warpage=0,
    taper=0,
    chord_dev=0,
    tetra_collapse=0,
    cell_squish_2d=0,
    equi_skew_2d=0,
    cell_squish_3d=0,
    equi_skew_3d=0,
    time_step=0,
    reserved_1=0,
    reserved_2=0,
    reserved_3=0,
    reserved_4=0,
)

batch_options = [
    "geometry_cleanup_flag    1",
    "meshing_flag                      5",
    "element_size                      5.0",
    "element_type                      2",
    "mesh_align                        3",
    "element_order                     1",
    "surf_component                    1",
    "feature_angle                     30.0",
    "holes_table_begin",
    "appl_surf(1)"
    "appl_solid(0)"
    "appl_cordsfiles(0)"
    "appl_flanged_suppr(1)"
    "flanged_suppr_height(1.4)"
    "narrow_slots_type(0)"
    "abs_fixed_nodes_count_max(-8)"
    "rad(0.0,2.2) do action(1) washer(0) ",
    "rad(2.2,3.01) do action(0) elems(4) washer(0) ",
    "rad(3.01,4.7) do action(0) elems(6) washer(1) layers(3.5) ",
    "rad(4.7,9.0) do action(0) elems(8) washer(1) layers(0.75*radius) ",
    "rad(9.0,11.0) do action(0) elems(8) washer(1) layers(7.0) ",
    "rad(11.0,20) do action(0) elems(8) washer(1) layers(auto) ",
    "rad(0.0,2.2) solid(1) do action(1) ",
    "rad(2.2,3.01) solid(1) do action(0) elems(4) ",
    "rad(3.01,20) solid(1) do action(0) elems(6) ",
    "holes_table_end",
    "edge_fillet_recognition           1",
    "max_fillet_radius                 5.0",
    "surface_fillet_table_begin",
    "surface_fillet_recognition(1)"
    "minimize_transitions(1)"
    "rad(0,2.2) wid(3.0,6.2) do split(suppress_on)"
    "rad(2.2,15) wid(3.4,6.2) do elems(1)"
    "rad(0,25.0) wid(6.2,9.2) do elems(2)"
    "rad(0,35.0) wid(9.2,12.5) do elems(3)"
    "rad(0,40.0) wid(12.5,25.0) do chordal_deviation(0.2)"
    "surface_fillet_table_end",
    "del_dupl_surfs_flag               2",
    "del_dupl_surfs_tol                -1",
    "edges_stitch_flags                0",
    "max_edges_stitch_tol              -1.0",
    "fix_overlapsurfs_flag             1",
    "overlapsurfs_maxtangangle         -1.0",
    "narrow_surfs_merge_width          -1.0",
    "narrow_surfs_treat_flags          3",
    "beads_suppression                 1",
    "beads_recognition                 1",
    "minimal_beads_height              1.4",
    "beads_treat_flags                 0",
    "flange_recognition                1",
    "flange_elements_across            3",
    "flange_max_width                  30.0",
    "flange_min_width                  8.0",
    "flanges_treat_flags               1",
    "flange_max_remove_width           -1.0",
    "appl_tria_reduction               1",
    "tria_redu_max_elemsize            auto",
    "tria_redu_min_elemsize            auto",
    "trias_around_holes                0",
    "common_mesh_flow                  0",
    "extract_thinsolids                1",
    "midsurf_method                    3",
    "thinsolid_ratio                   0.3",
    "max_thickness                     10.0",
    "extract_feature_angle             25.0",
    "pre_midsurf_cleanup               1",
    "direct_midmesh                    0",
    "ignore_flat_edges                 1",
    "flatten_connections               0",
    "defeat_open_width_on              1",
    "defeat_open_width                 1.0",
    "supp_proxim_edges_on              1",
    "supp_proxim_edges                 0.5",
    "combine_nonmanifold_on            1",
    "combine_nonmanifold               0.5",
    "midmesh_extact_elem_size          10.0",
    "remove_logo                       1",
    "logo_max_size                     30.0",
    "logo_max_height                   1.4",
    "logo_min_concavity                1.0",
    "threads_removal                   0",
    "threads_toremove_max_depth        5.0",
    "threads_replacediametertype       -2",
    "folded_elems_angle                150.0",
    "smooth_elems_target               0.2",
    "fillets_mesh_flow                 0",
    "failed_elems_cleanup_flgs         8",
    "move_nodes_across_feature_edges   1",
    "featureedge_nodes_moveacross_max  0.1",
    "move_nodes_across_free_edges      1",
    "freeedge_nodes_moveacross_max     0.05",
    "move_normal_flag                  1",
    "move_normal_dist                  0.8",
    "divide_warped_quads               1",
    "ignore_comps_boundary             0",
    "gen_topology_prepare_flags        7",
    "cleanup_comp_flag                 0 ",
    "comp_select                        ",
    "use_wildcards_for_compsnames      0",
    "cleanup_tolerances                auto",
    "suppress_features_rate            0",
    "feat_charsize_method              0",
    "custom_feat_suppr_maxangle        25.0",
    "uncond_constr_lines_suppress      0",
    "aggressive_fillet_lines_suppress  0",
]

model.createbatchparamsfromstrings(strings=batch_options)

elem_collection = hm.Collection(model, ent.Element)

model.min_size_node_movement(collection=elem_collection)