Skip to content

Commit 5720df1

Browse files
srpyprimewaltersmaninad-kamat
authored
Create IGA (#679)
Co-authored-by: Martin Walters <[email protected]> Co-authored-by: Ninad Kamat <[email protected]>
1 parent 6c7608e commit 5720df1

File tree

4 files changed

+187
-0
lines changed

4 files changed

+187
-0
lines changed

‎doc/source/images/model_iga.png‎

109 KB
Loading

‎doc/source/user_guide/iga.rst‎

Lines changed: 183 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,183 @@
1+
.. _ref_index_IGA:
2+
3+
*********************
4+
Isogeometric analysis
5+
*********************
6+
7+
*This is a Beta feature. API Behavior and Implementation may change in future.*
8+
9+
Isogeometric Analysis (IGA) is a new approach using NURBS to capture the CAD geometry accurately than the FE analysis.
10+
The FE analysis discretize the CAD geometry approximately into smaller elements to capture the features.
11+
This approximation may affect the accuracy of the result and increase the computational cost.
12+
IGA uses spline to exactly represent the CAD geometry to analyse the geometry and solver solves on the splines.
13+
14+
In PyPrimeMesh, IGA-Quad to Spline allows you to extract control points and splines based on the input quadrilateral surface mesh and export it as LS-DYNA IGA K file for the IGA solver.
15+
16+
The prerequisites required for preparing Input CAD Model for Quad to Spline conversion:
17+
18+
* Clean up the input geometry in PyPrimeMesh.
19+
20+
* Generates full quad mesh on the input geometry.
21+
22+
* Perform mesh edit operations to reduce the triangles.
23+
24+
IGA Quad to Spline performs the following:
25+
26+
1. Execute quad to spline operation using any of the following options:
27+
28+
- When you provide Ignore Features, ignores all the features while converting the input geometry to spline.
29+
- When you provide Use Angle, captures the provided angle while creating the spline for the input geometry.
30+
- When you provide Use Edges, uses the provided edges while creating spline for the input geometry.
31+
32+
2. Checks if any Negative Jacobian values are present while creating splines.
33+
34+
3. Export Splines as LS-DYNA IGA K file if no Negative Jacobian values are present in the input geometry.
35+
36+
4. Provides the file to the LS-DYNA IGA solver.
37+
38+
39+
The below example shows IGA Quad to spline conversion:
40+
41+
1. Import the geometry.
42+
43+
.. code-block:: python
44+
45+
file_io = prime.FileIO(model)
46+
res = file_io.read_pmdat(r"pillar.pmdat", prime.FileReadParams(model=model))
47+
g = Graphics(model)
48+
g()
49+
50+
.. figure:: ../images/model_iga.png
51+
52+
2. Check whether the model is a topology or mesh part.
53+
54+
.. code-block:: python
55+
56+
cad_mesh_part = model.parts
57+
for part in cad_mesh_part:
58+
if part.get_topo_faces():
59+
geom_part_name = part.name
60+
print(geom_part_name)
61+
summary_res = part.get_summary(
62+
prime.PartSummaryParams(
63+
model=model,
64+
print_id=False,
65+
print_mesh=True,
66+
)
67+
)
68+
print("Geometry Part")
69+
else:
70+
mesh_part_name = part.name
71+
print(mesh_part_name)
72+
summary_res = part.get_summary(
73+
prime.PartSummaryParams(
74+
model=model,
75+
print_id=False,
76+
print_mesh=True,
77+
)
78+
)
79+
print("Mesh Part")
80+
81+
**Output:**
82+
83+
.. code-block:: pycon
84+
85+
Geometry Part
86+
87+
3. Define the input scope for the geometry or mesh part.
88+
89+
.. code-block:: python
90+
91+
input_scope = prime.ScopeDefinition(model, part_expression=mesh_part.name)
92+
geom_topofaces = geom_part.get_topo_faces()
93+
geom_topoedges = geom_part.get_topo_edges()
94+
95+
4. Initialize QuadToSpline and provide the required parameters in QuadToSplineParams to perform the quad to spline conversion.
96+
97+
.. code-block:: python
98+
99+
zone_name_1 = "zone1_thk_0.8"
100+
zone_name_2 = "zone2_thk_1.0"
101+
zone_name_3 = "zone3_thk_1.2"
102+
shell_thickness_zone_1 = 0.8
103+
shell_thickness_zone_2 = 1.0
104+
shell_thickness_zone_3 = 1.2
105+
QuadToSpline = prime.QuadToSpline(model)
106+
quad_to_spline_params = prime.QuadToSplineParams(model)
107+
quad_to_spline_params.feature_capture_type = prime.SplineFeatureCaptureType.BYANGLE
108+
quad_to_spline_params.corner_angle = 40
109+
quad_to_spline_params.project_on_geometry = False
110+
quad_to_spline_params.separate_by_zone = True
111+
quad_to_spline_params.zone_name_shell_thickness_pairs = {
112+
zone_name_1: shell_thickness_zone_1,
113+
zone_name_2: shell_thickness_zone_2,
114+
zone_name_3: shell_thickness_zone_3,
115+
}
116+
unstructured_spline_fitting = QuadToSpline.convert_quad_to_spline(
117+
input_scope, quad_to_spline_params
118+
)
119+
print("Quad to Spline fitting status: ", unstructured_spline_fitting)
120+
121+
**Output:**
122+
123+
.. code-block:: pycon
124+
125+
This API convert_quad_to_spline is a Beta. API Behavior and implementation may change in future.
126+
Quad to Spline fitting status: error_code : ErrorCode.NOERROR
127+
warning_code : WarningCode.NOWARNING
128+
spline_ids : []
129+
130+
5. Get the unstructured spline created.
131+
132+
.. code-block:: python
133+
134+
spline1 = unstructured_spline_fitting.spline_ids
135+
unstructured_spline_surface = mesh_part.get_unstructured_spline_surface()
136+
print(unstructured_spline_surface)
137+
138+
**Output:**
139+
140+
.. code-block:: pycon
141+
142+
This API get_unstructured_spline_surface is a Beta. API Behavior and implementation may change in future.
143+
id : 2
144+
spline_refinement_level : 5
145+
control_points : [-60.7216 -0.598581 428.905 ... -47.2185 87.6738 23.852 ]
146+
spline_points : [-60.6697 -0.566523 428.971 ... -47.0478 9.97661 58.3805 ]
147+
bad_spline_points_indices : []
148+
deviation_array : [0.00214125 0.0150002 0.017894 ... 0.00113307 0.0106386 0.0104887 ]
149+
invalid_jacobian_elements_count : 0
150+
average_mesh_size : 4.21427
151+
elements_count : 2194
152+
shell_thickness : 0.0001
153+
154+
6. Check the quality of the created spline.
155+
156+
.. code-block:: python
157+
158+
negative_jacobian = unstructured_spline_surface.invalid_jacobian_elements_count
159+
deviation_array = unstructured_spline_surface.deviation_array
160+
max_abs_deviation = max(deviation_array)
161+
control_points_count = len(unstructured_spline_surface.control_points) / 3
162+
spline_points_count = len(unstructured_spline_surface.spline_points) / 3
163+
print("Invalid/Negative Jacobian count: ", negative_jacobian)
164+
print("Control points count: ", control_points_count)
165+
print("Spline points count: ", spline_points_count)
166+
print("Max Deviation: ", max_abs_deviation)
167+
168+
**Output:**
169+
170+
.. code-block:: pycon
171+
172+
Invalid/Negative Jacobian count: 0
173+
Control points count: 5585.0
174+
Spline points count: 78984.0
175+
Max Deviation: 1.27418
176+
177+
7. Write the created .k file to the specified location and export to LS-DYNA.
178+
179+
.. code-block:: python
180+
181+
lsdyna_iga_export_result = prime.FileIO(model).export_lsdyna_iga_keyword_file(
182+
r"E:\Test\newspline.k", prime.ExportLSDynaIgaKeywordFileParams(model)
183+
)

‎doc/source/user_guide/index.rst‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -18,6 +18,7 @@ This section provides an overview of how you use PyPrimeMesh for mesh preparatio
1818
surfer
1919
wrapper
2020
automesh
21+
iga
2122
multizone
2223
stacker
2324
matchmorph

‎doc/styles/Vocab/ANSYS/accept.txt‎

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -8,13 +8,16 @@ CAD
88
conformally
99
[Dd]efeature
1010
defeaturing
11+
discretize
1112
Fluent Meshing
1213
Fluent Meshing's
1314
geodesical
1415
hexahedra
1516
hexcore
1617
ignore_orientation
1718
ignore_self_proximity
19+
IGA
20+
[Ii]sogeometric
1821
[Ll]ucid
1922
Material Point Manager
2023
[Mm]eshedgeodesic

0 commit comments

Comments
 (0)