readme

Author: NickNick9

iga/README.md

@@ -1,5 +1,7 @@
-# Fluid Dynamics Examples
+# Iga Examples
 
 ## Use Cases
+- External Boundary Circle (NURBS) 
 
 ## Validation Cases
+- External Boundary Circle (NURBS) 

iga/use_cases/README.md

@@ -1,4 +1,56 @@
-# Use Cases
+# Use Cases IGA – External Boundary Circle (NURBS) — README.txt
+
+Short description
+This example runs a 2D IGA structural model whose outer boundary is a NURBS circle. A manufactured solution is enforced to validate the setup.
+
+Files
+- ProjectParameters.json
+- materials.json
+- nurbs_files/circle_nurbs.json
+- run_and_post.py (optional)
+
+Geometry / modeling (very brief)
+- ImportNurbsSbmModeler loads the circle NURBS into “initial_skin_model_part_out”.
+- NurbsGeometryModelerSbm builds the analysis surface (order [2,2], knot spans [20,20]) and creates “skin_model_part”.
+- IgaModelerSbm creates:
+  • SolidElement on IgaModelPart.StructuralAnalysisDomain
+  • SbmSolidCondition on SurfaceEdge (brep_ids: [2]) → IgaModelPart.SBM_Support_outer
+
+Manufactured BCs and loads
+- Displacement on outer boundary:
+  u = [ -cos(x)*sinh(y),  sin(x)*cosh(y), 0.0 ]
+- Body force in the domain (consistent with the above):
+  BODY_FORCE = [
+    -1000*(1+0.3)/(1-0.3*0.3)*cos(x)*sinh(y),
+    -1000*(1+0.3)/(1-0.3*0.3)*sin(x)*cosh(y),
+    0.0
+  ]
+
+Solver (key settings)
+- Static, nonlinear; OpenMP
+- Single time step: dt = 0.1, end_time = 0.1
+- Linear solver: LinearSolversApplication.sparse_lu
+
+Minimal materials.json (example)
+Use plane strain (or plane stress) linear elastic; keep it consistent with ν=0.3:
+{
+  "properties": [{
+    "model_part_name": "IgaModelPart.StructuralAnalysisDomain",
+    "properties_id": 1,
+    "Material": {
+      "constitutive_law": { "name": "LinearElasticPlaneStrain2DLaw" },
+      "Variables": {
+        "YOUNG_MODULUS": 1000.0,
+        "POISSON_RATIO": 0.3,
+        "DENSITY": 1.0
+      }
+    }
+  }]
+}
+
+Run:
+  python3 run_and_post.py        # to reproduce the error
+  python3 convergence.py         # for the convergence analysis
+  python3 plot_surrogate_boundaries.py  # to visualize the surrogate and true boundaries
 
-This folder contains the validation cases: