[GeoMechanicsApplication] Extend ApplyCPhiReductionProcess to use Mohr-Coulomb constitutive model by markelov208 · Pull Request #14085 · KratosMultiphysics/Kratos

markelov208 · 2025-12-22T15:58:29Z

📝 Description
A brief description of the PR.

added usage of GEO_FRICTION_ANGLE and GEO_COHESION
modified checks of input data and changed the corresponding unit tests
modified c_phi_reduction_process.py to have two tests with implementations of Mohr-Coulomb model from MohrCoulomb64 library and internal Kratos model.
updated README.md file
added InitializeParametersForInternalMohrCoulombModel to initialize material properties for the internal Mohr-Coulomb model

…-coulomb

WPK4FEM

Hi Gennady,
Generally you have made the internal MC model availably for C Phi reduction. I think its good to use the names of the allowed constitutive laws for discrimination in the if, else if conditions and then do things to the parameters. The integration test files can be shrunk somewhat, by removing information that is not going to be used ( I may well be the cause of this myself as you probably started from existing files for the new tests )

I hope that Anne or Richard also will have a look.
Thank you, Wijtze Pieter

WPK4FEM · 2026-03-05T12:56:19Z

applications/GeoMechanicsApplication/custom_processes/apply_c_phi_reduction_process.cpp

+            if (r_properties.Has(GEO_COHESION)) {
+                check_properties.Check(GEO_COHESION);
+                check_properties.Check(GEO_FRICTION_ANGLE);
+            } else {
+                check_properties.CheckAvailability(UMAT_PARAMETERS);
+                check_properties.Check(INDEX_OF_UMAT_PHI_PARAMETER, 1,
+                                       static_cast<int>(r_properties[UMAT_PARAMETERS].size()));
+                check_properties.Check(INDEX_OF_UMAT_C_PARAMETER, 1,
+                                       static_cast<int>(r_properties[UMAT_PARAMETERS].size()));
+            }


GEO_COHESION may be there due to a request for capacity output. I think that the if and the else if condition should use the constitutive law to discriminate. So check for the MohrCoulomb ( continuum and interface law ) and the UDSM law, and then check the properties of their parameters.

Thank you for the info. Now it checks for UDSM model and else for others.

WPK4FEM · 2026-03-05T13:00:19Z

applications/GeoMechanicsApplication/custom_processes/apply_c_phi_reduction_process.cpp

+        p_new_properties->SetValue(GEO_COHESION, ReducedC);
+    } else {
+        // Overwrite C and Phi in the UMAT_PARAMETERS
+        auto Umat_parameters = r_properties[UMAT_PARAMETERS];


umat_parameters is a local variable starting with lower case according to the stylesheet.

WPK4FEM · 2026-03-05T13:02:10Z

applications/GeoMechanicsApplication/custom_processes/apply_c_phi_reduction_process.cpp

+    const auto& r_properties = rElement.GetProperties();
+    Properties::Pointer p_new_properties = Kratos::make_shared<Properties>(r_properties);
+
+    if (r_properties.Has(GEO_FRICTION_ANGLE)) {


Also here its probably better to distinguish based on the constitutive law.

Agreed, now it is like for Check function

WPK4FEM · 2026-03-05T13:04:10Z

...sApplication/tests/C-Phi_reduction_process/Mohr_Coulomb_model/MaterialParameters_stage1.json

+              "SATURATED_SATURATION"     :  1.0,
+              "K0_MAIN_DIRECTION"        :  1,
+              "K0_VALUE_XX"              :  0.42642356364895390389196808717384,
+              "K0_VALUE_YY"              :  0.42642356364895390389196808717384,


The K0 main direction is 1 ( Y direction ). Then the K0_VALUE_YY is not really used, but interpreted as 1. If possible remove K0_VALUE_YY, otherwise please set it to 1.

The values for XX and ZZ are a surprise too. In the next stage the material has a friction angle of 30 deg. That would give a K0 = 1 - sin 30 = 0.5

Now K0_VALUE_YY=1. the angle is 35 degs, not 30 degs.

WPK4FEM · 2026-03-05T13:08:20Z

...Application/tests/C-Phi_reduction_process/Mohr_Coulomb_model64/ProjectParameters_stage1.json

+        "rayleigh_k": 0.0,
+        "rayleigh_m": 0.0,
+        "reduction_factor": 0.5,


for a quasistatic analysis, Rayleigh parameters are not used.

WPK4FEM · 2026-03-05T13:18:35Z

...Application/tests/C-Phi_reduction_process/Mohr_Coulomb_model64/ProjectParameters_stage2.json

+                        "plane_output":        [],
+                        "nodal_results":       ["DISPLACEMENT"]
+                    },
+                    "point_data_configuration":  []


the empty point_data_configuration can probably be removed.

WPK4FEM · 2026-03-05T13:18:54Z

...Application/tests/C-Phi_reduction_process/Mohr_Coulomb_model64/ProjectParameters_stage2.json

+            "active":          [true,true,true],
+            "is_fixed":        [true,false,true],


Please set the Z components to false

WPK4FEM · 2026-03-05T13:19:22Z

...Application/tests/C-Phi_reduction_process/Mohr_Coulomb_model64/ProjectParameters_stage2.json

+                    "model_part_name": "PorousDomain.All_Nodes",
+                    "out_of_plane_direction": 2,
+                    "second_reference_coordinate": [ 40.0, -10.0, 0.0 ],
+                    "specific_weight": 10000.0,


conflicting with the water density in the material parameters.

assigned to 0

WPK4FEM · 2026-03-05T13:19:49Z

...Application/tests/C-Phi_reduction_process/Mohr_Coulomb_model64/ProjectParameters_stage2.json

+            "active":          [true,true,true],
+            "is_fixed":        [true,true,true],


Please set the Z components to false.

WPK4FEM · 2026-03-05T13:20:57Z

...MechanicsApplication/tests/cpp_tests/custom_processes/test_apply_c_phi_reduction_process.cpp


    KRATOS_EXPECT_EXCEPTION_IS_THROWN(
-        (ApplyCPhiReductionProcess{model, parameters}.ExecuteInitializeSolutionStep()),
+        (ApplyCPhiReductionProcess{model, parameters}.Check()),


can the ExecuteInitializeSolutionStep really be omitted?

Yes, because I moved checks from various runtime functions to Check. ExecuteInitializeSolutionStep was used here just to check the input.

…-coulomb

markelov208

Hi Wijtze Pieter, many thanks for the thorough review.

markelov208 · 2026-03-10T16:21:47Z

...MechanicsApplication/tests/cpp_tests/custom_processes/test_apply_c_phi_reduction_process.cpp


    KRATOS_EXPECT_EXCEPTION_IS_THROWN(
-        (ApplyCPhiReductionProcess{model, parameters}.ExecuteInitializeSolutionStep()),
+        (ApplyCPhiReductionProcess{model, parameters}.Check()),


Yes, because I moved checks from various runtime functions to Check. ExecuteInitializeSolutionStep was used here just to check the input.

markelov208 · 2026-03-10T16:22:46Z

applications/GeoMechanicsApplication/custom_processes/apply_c_phi_reduction_process.cpp

+            if (r_properties.Has(GEO_COHESION)) {
+                check_properties.Check(GEO_COHESION);
+                check_properties.Check(GEO_FRICTION_ANGLE);
+            } else {
+                check_properties.CheckAvailability(UMAT_PARAMETERS);
+                check_properties.Check(INDEX_OF_UMAT_PHI_PARAMETER, 1,
+                                       static_cast<int>(r_properties[UMAT_PARAMETERS].size()));
+                check_properties.Check(INDEX_OF_UMAT_C_PARAMETER, 1,
+                                       static_cast<int>(r_properties[UMAT_PARAMETERS].size()));
+            }


Thank you for the info. Now it checks for UDSM model and else for others.

markelov208 · 2026-03-10T16:22:58Z

applications/GeoMechanicsApplication/custom_processes/apply_c_phi_reduction_process.cpp

+        p_new_properties->SetValue(GEO_COHESION, ReducedC);
+    } else {
+        // Overwrite C and Phi in the UMAT_PARAMETERS
+        auto Umat_parameters = r_properties[UMAT_PARAMETERS];


markelov208 · 2026-03-10T16:23:35Z

applications/GeoMechanicsApplication/custom_processes/apply_c_phi_reduction_process.cpp

+    const auto& r_properties = rElement.GetProperties();
+    Properties::Pointer p_new_properties = Kratos::make_shared<Properties>(r_properties);
+
+    if (r_properties.Has(GEO_FRICTION_ANGLE)) {


Agreed, now it is like for Check function

markelov208 · 2026-03-10T16:24:18Z

...sApplication/tests/C-Phi_reduction_process/Mohr_Coulomb_model/MaterialParameters_stage1.json

+              "SATURATED_SATURATION"     :  1.0,
+              "K0_MAIN_DIRECTION"        :  1,
+              "K0_VALUE_XX"              :  0.42642356364895390389196808717384,
+              "K0_VALUE_YY"              :  0.42642356364895390389196808717384,


Now K0_VALUE_YY=1. the angle is 35 degs, not 30 degs.

markelov208 · 2026-03-10T16:27:01Z

...Application/tests/C-Phi_reduction_process/Mohr_Coulomb_model64/ProjectParameters_stage2.json

+        "desired_iterations":                 4,
+        "max_radius_factor":                  10.0,
+        "min_radius_factor":                  0.1,


markelov208 · 2026-03-10T16:27:08Z

...Application/tests/C-Phi_reduction_process/Mohr_Coulomb_model64/ProjectParameters_stage2.json

+                        "plane_output":        [],
+                        "nodal_results":       ["DISPLACEMENT"]
+                    },
+                    "point_data_configuration":  []


markelov208 · 2026-03-10T16:27:18Z

...Application/tests/C-Phi_reduction_process/Mohr_Coulomb_model64/ProjectParameters_stage2.json

+            "active":          [true,true,true],
+            "is_fixed":        [true,false,true],


markelov208 · 2026-03-10T16:27:28Z

...Application/tests/C-Phi_reduction_process/Mohr_Coulomb_model64/ProjectParameters_stage2.json

+                    "model_part_name": "PorousDomain.All_Nodes",
+                    "out_of_plane_direction": 2,
+                    "second_reference_coordinate": [ 40.0, -10.0, 0.0 ],
+                    "specific_weight": 10000.0,


assigned to 0

markelov208 · 2026-03-10T16:27:34Z

...Application/tests/C-Phi_reduction_process/Mohr_Coulomb_model64/ProjectParameters_stage2.json

+            "active":          [true,true,true],
+            "is_fixed":        [true,true,true],


added usage of GEO_FRICTION_ANGLE and GEO_COHESION

7023b55

markelov208 self-assigned this Dec 22, 2025

markelov208 requested a review from a team as a code owner December 22, 2025 15:58

markelov208 linked an issue Dec 23, 2025 that may be closed by this pull request

[GeoMechanicsApplication] Extend ApplyCPhiReductionProcess to use Mohr-Coulomb constitutive model #14083

Open

markelov208 added 4 commits February 26, 2026 13:55

Merge branch 'master' into geo/14083-extend-c-phi-reduction-with-mohr…

a16ec9e

…-coulomb

removed SetValueAtElement function

2a5ae79

used two Mohr-Coulomb models

47706bf

corrected README.md

8ffc0ea

markelov208 requested review from WPK4FEM, avdg81 and rfaasse February 27, 2026 10:02

Merge branch 'master' into geo/14083-extend-c-phi-reduction-with-mohr…

df61b9f

…-coulomb

WPK4FEM reviewed Mar 5, 2026

View reviewed changes

markelov208 added 6 commits March 10, 2026 12:05

added InitializeParametersForInternalMohrCoulombModel

6ef9d15

Merge branch 'master' into geo/14083-extend-c-phi-reduction-with-mohr…

91b8c9d

…-coulomb

added function InitializeParametersForInternalMohrCoulombModel

58ae3a5

corrected material/project parameters and added common folder

e51d7ec

corrected Umat_parameters

3d2bd47

made checks and actions dependent on material model

ddd9caf

markelov208 commented Mar 10, 2026

View reviewed changes

markelov208 requested a review from WPK4FEM March 10, 2026 16:31

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markelov208 commented Dec 22, 2025 •

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