Add IGA Validation Examples

iga/README.md

@@ -1,10 +1,19 @@
 # Iga Examples
 
+This folder contains examples related to Isogeometric Analysis in Kratos.
+
+They are realized using the IgaApplication
+
+The Examples are continuously updated and extended
+
 ## Use Cases
 - [External Boundary Circle (NURBS)](https://github.com/KratosMultiphysics/Examples/blob/master/iga/use_cases/external_boundary_circle_with_nurbs/README.md)
 - [IGA Single-Patch Shell in Membrane Action with Weak Supports and Line Load](https://github.com/KratosMultiphysics/Examples/blob/master/iga/use_cases/iga_shell_3p_single_patch/README.md)
 - [3D Laplacian on an Embedded Cube with SBM](https://github.com/KratosMultiphysics/Examples/blob/master/iga/use_cases/laplacian_3d_cube_sbm/README.md)
 
 ## Validation Cases
-
-# Use Cases
+- [Buckling Analysis - Single Patch - Cantilever Beam](https://github.com/KratosMultiphysics/Examples/blob/master/iga/validation/buckling_analysis_single_patch_cantilever_beam/README.md)
+- [Geometric Linear Analysis - Single Patch - Scordelis-Lo Roof](https://github.com/KratosMultiphysics/Examples/blob/master/iga/validation/geometric_linear_analysis_single_patch_scordelis_lo_roof/README.md)
+- [Geometric Linear Analysis - Trimmed Patch - Plate with Hole](https://github.com/KratosMultiphysics/Examples/blob/master/iga/validation/geometric_linear_analysis_trimmed_patch_plate_with_hole/README.md)
+- [Geometric Non-Linear Analysis - Multi Patch - Cantilever Beam](https://github.com/KratosMultiphysics/Examples/blob/master/iga/validation/geometric_nonlinear_analysis_multi_patch_cantilever_beam/README.md)
+- [Geometric Non-Linear Analysis - Single Patch - Cantilever Beam](https://github.com/KratosMultiphysics/Examples/blob/master/iga/validation/geometric_nonlinear_analysis_single_patch_cantilever_beam/README.md)

iga/validation/README.md

@@ -2,3 +2,8 @@
 
 This folder contains the validation cases:
 
+- [Buckling Analysis - Single Patch - Cantilever Beam](buckling_analysis_single_patch_cantilever_beam/README.md)
+- [Geometric Linear Analysis - Single Patch - Scordelis-Lo Roof](geometric_linear_analysis_single_patch_scordelis_lo_roof/README.md)
+- [Geometric Linear Analysis - Trimmed Patch - Plate with Hole](geometric_linear_analysis_trimmed_patch_plate_with_hole/README.md)
+- [Geometric Non-Linear Analysis - Multi Patch - Cantilever Beam](geometric_nonlinear_analysis_multi_patch_cantilever_beam/README.md)
+- [Geometric Non-Linear Analysis - Single Patch - Cantilever Beam](geometric_nonlinear_analysis_single_patch_cantilever_beam/README.md)

iga/validation/buckling_analysis_single_patch_cantilever_beam/README.md

@@ -0,0 +1,49 @@
+# Buckling Analysis - Single Patch - Cantilever Beam
+
+**Author:** Aakash Ravichandran
+
+**Kratos version:** 10.2
+
+**Source files:** [Buckling Analysis - Single Patch - Cantilever Beam](https://github.com/KratosMultiphysics/Examples/tree/master/iga/validation/buckling_analysis_single_patch_cantilever_beam/source)
+
+## Problem definition
+
+This example presents the validation of buckling analysis in Kratos with Isogeometric Analysis.
+
+<div align="center">
+<img src="data/Reference_Model.png" alt="Displacement" width="600">
+
+*Structural System [1]*
+</div>
+
+
+The cantilever beam is modeled using single NURBS patch with the Shell3pElement. The CAD model is constructed with single span B-spline surfaces and has a curve degree of 2 in both directions of the plane. Additional refinement is applied in Kratos, by increasing the curve degree to 4 in both axes and inserting 4 knots in the width and 20 knots along the length of the beam.
+
+## Results
+
+The buckling load factors are shown in table below. The corresponding buckling modes are shown in image below.  
+
+<div align="center">
+
+|  | Reference | Kratos |
+| :--- | :--- | :--- |
+| $\lambda_{cr}^{(1)}$ | 4.1123 | 4.06977 |
+| $\lambda_{cr}^{(2)}$ | 16.449 | 16.1693 |
+| $\lambda_{cr}^{(3)}$ | 37.011 | 36.6759 |
+| $\lambda_{cr}^{(4)}$ | 102.81 | 102.106 |
+
+</div>
+
+| Buckling Mode Shape 1 | Buckling Mode Shape 2 |
+| :---: | :---: |
+| ![Buckling Mode Shape 1](data/Buckling_Mode_1.png) | ![Buckling Mode Shape 2](data/Buckling_Mode_2.png) |
+
+| Buckling Mode Shape 3 | Buckling Mode Shape 4 |
+| :---: | :---: |
+| ![Buckling Mode Shape 3](data/Buckling_Mode_3.png) | ![Buckling Mode Shape 4](data/Buckling_Mode_4.png) |
+
+
+
+## References
+
+1. Altair Engineering, Inc. (2026). *OS-V: 0080 Buckling of Shells and Composites with Offset*. In Altair OptiStruct Verification Problems. [link](https://help.altair.com/hwsolvers/os/topics/solvers/os/buckling_of_shells_and_composites_with_offset_verification_r.htm)

iga/validation/buckling_analysis_single_patch_cantilever_beam/source/ProjectParameters.json

@@ -0,0 +1,177 @@
+{
+    "problem_data": {
+        "problem_name": "Buckling_Analysis",
+        "echo_level": 0,
+        "parallel_type": "OpenMP",
+        "start_time": 0,
+        "end_time": 0.1
+    },
+    "solver_settings": {
+        "model_part_name": "IgaModelPart",
+        "domain_size": 1,
+        "echo_level": 1,
+        "buffer_size": 2,
+        "analysis_type": "linear",
+        "model_import_settings": {
+            "input_type": "use_input_model_part"
+        },
+        "material_import_settings": {
+            "materials_filename": "materials.json"
+        },
+        "time_stepping": {
+            "time_step": 1
+        },
+        "rotation_dofs": false,
+        "reform_dofs_at_each_step": false,
+        "line_search": false,
+        "compute_reactions": true,
+        "clear_storage": false,
+        "move_mesh_flag": true,
+        "convergence_criterion": "residual_criterion",
+        "displacement_relative_tolerance": 0.0001,
+        "displacement_absolute_tolerance": 1E-09,
+        "residual_relative_tolerance": 0.0001,
+        "residual_absolute_tolerance": 1E-09,
+        "max_iteration": 1,
+        "builder_and_solver_settings" : {
+            "advanced_settings": {},
+            "use_block_builder": true,
+            "use_lagrange_BS": false
+        },
+        "solver_type": "prebuckling",
+        "buckling_settings"     : {
+            "initial_load_increment"    : 1.0,
+            "small_load_increment"      : 0.0005,
+            "path_following_step"       : 0.5,
+            "convergence_ratio"         : 0.05,
+            "make_matrices_symmetric"   : true
+        },
+        "eigensolver_settings" : {
+            "solver_type"           : "eigen_eigensystem",
+            "max_iteration"         : 1000,
+            "tolerance"             : 1e-6,
+            "number_of_eigenvalues" : 5,
+            "echo_level"            : 1
+        },
+        "auxiliary_variables_list": [],
+        "auxiliary_dofs_list": [],
+        "auxiliary_reaction_list": []
+    },
+    "modelers": [
+        {
+            "modeler_name": "CadIoModeler",
+            "Parameters": {
+                "echo_level": 0,
+                "cad_model_part_name": "IgaModelPart",
+                "geometry_file_name": "geometry.cad.json",
+                "output_geometry_file_name": "Buckling_Analysis_kratos_0.georhino.json"
+            }
+        },
+        {
+            "modeler_name": "RefinementModeler",
+            "Parameters": {
+                "echo_level": 0,
+                "physics_file_name": "refinements.iga.json"
+            }
+        },
+        {
+            "modeler_name": "IgaModeler",
+            "Parameters": {
+                "echo_level": 0,
+                "cad_model_part_name": "IgaModelPart",
+                "analysis_model_part_name": "IgaModelPart",
+                "physics_file_name": "physics.iga.json"
+            }
+        }
+    ],
+    "processes": {
+        "additional_processes": [
+            {
+                "kratos_module": "IgaApplication",
+                "python_module": "output_quadrature_domain_process",
+                "Parameters": {
+                    "output_file_name": "Buckling_Analysis_kratos_shell_1_integrationdomain.json",
+                    "model_part_name": "IgaModelPart.StructuralAnalysis_1",
+                    "output_geometry_elements": true,
+                    "output_geometry_conditions": false
+                }
+            },
+            {
+                "kratos_module": "IgaApplication",
+                "python_module": "output_quadrature_domain_process",
+                "Parameters": {
+                    "output_file_name": "Buckling_Analysis_kratos_support_2_integrationdomain.json",
+                    "model_part_name": "IgaModelPart.Support_2",
+                    "output_geometry_elements": false,
+                    "output_geometry_conditions": true
+                }
+            },
+            {
+                "kratos_module": "IgaApplication",
+                "python_module": "output_eigen_values_process",
+                "Parameters": {
+                    "output_file_name": "Buckling_Analysis_kratos_eigen_values.post.res",
+                    "model_part_name": "IgaModelPart"
+                }
+            }
+        ],
+        "dirichlet_process_list": [
+            {
+                "kratos_module": "KratosMultiphysics",
+                "python_module": "assign_vector_variable_process",
+                "Parameters": {
+                    "model_part_name": "IgaModelPart.Support_2",
+                    "variable_name": "DISPLACEMENT",
+                    "value": [
+                        0,
+                        0,
+                        0
+                    ],
+                    "interval": [
+                        0,
+                        "End"
+                    ]
+                }
+            },
+            {
+                "kratos_module": "KratosMultiphysics",
+                "python_module": "assign_vector_variable_process",
+                "Parameters": {
+                    "model_part_name": "IgaModelPart.Support_2_Rotational",
+                    "variable_name": "DISPLACEMENT",
+                    "value": [
+                        0,
+                        0,
+                        0
+                    ],
+                    "interval": [
+                        0,
+                        "End"
+                    ]
+                }
+            }
+        ],
+        "neumann_process_list": [
+            {
+                "kratos_module": "KratosMultiphysics",
+                "python_module": "assign_vector_variable_to_conditions_process",
+                "Parameters": {
+                    "model_part_name": "IgaModelPart.Load_3",
+                    "variable_name": "DEAD_LOAD",
+                    "value": [
+                        -5,
+                        0,
+                        0
+                    ],
+                    "interval": [
+                        0,
+                        "End"
+                    ]
+                }
+            }
+        ]
+    },
+    "output_processes": {
+        "output_process_list": []
+    }
+}