Density update #186

streeve · 2025-02-05T14:57:28Z

Blocked by #142, and #200

Adds a density update using plastic strain

src/force/CabanaPD_ForceModels_PMB.hpp

stores list, handles iteration, and broken bonds

pabloseleson · 2025-04-10T19:40:50Z

src/CabanaPD_Force.hpp

-        Kokkos::parallel_reduce( policy, neigh_max, local_max_neighbors );
-        Kokkos::fence();
-        return local_max_neighbors;
+        neighbor.iterate( exec_space{}, weighted_volume, particles,


What does "neighbor.iterate" do? What is the difference with iterateLinear?

Moved to the neighbor PR (200)

pabloseleson · 2025-04-10T19:52:13Z

src/CabanaPD_HeatTransfer.hpp

-        , fracture_type( force.getBrokenBonds() )
+    HeatTransfer( const model_type model )
+        : base_type( typename base_type::model_type(
+              PMB{}, NoFracture{}, model.delta, model.K, model.temperature,


Is it needed to use "NoFracture" for HeatTransfer?

This should no longer be necessary

pabloseleson · 2025-04-10T19:53:40Z

src/CabanaPD_Neighbor.hpp

+  public:
+    using list_type =
+        Cabana::VerletList<MemorySpace, Cabana::FullNeighborTag,
+                           Cabana::VerletLayout2D, Cabana::TeamOpTag>;


What does it mean VerletLayout2D for a 3D code?

It does not refer to spatial dimension, but to the layout of the neighbor list itself

pabloseleson · 2025-04-10T19:57:39Z

src/CabanaPD_Neighbor.hpp

+                        const std::string label ) const
+    {
+        auto policy = makePolicy<ExecSpace>( particles );
+        Kokkos::parallel_for( label, policy, functor );


What is the difference between parallel_for and neighbor_parallel_for?

I assume this would explain the difference between iterate and iterateLinear.

That's correct

pabloseleson · 2025-04-10T20:00:29Z

src/CabanaPD_Neighbor.hpp

+    auto list() const { return _neigh_list; }
+
+    template <typename ParticleType>
+    void update( ParticleType& particles, const double cutoff )


What is this update function for?

Rebuild neighbors

pabloseleson · 2025-04-10T20:01:48Z

src/CabanaPD_Neighbor.hpp

+
+    // Only rebuild neighbor list as needed.
+    template <class ParticleType>
+    void update( const ParticleType& particles, const double search_radius,


Is this update function for contact?

pabloseleson · 2025-04-10T20:14:03Z

src/force/CabanaPD_LPS.hpp

    {
    }

-    template <class ParticleType, class ParallelType>


Where was all this deleted part moved to?

The new Dilatation class

pabloseleson · 2025-04-10T20:14:46Z

src/force/CabanaPD_LPS.hpp

    {
-        fracture_type::prenotch( exec_space, particles, prenotch, _neigh_list );


Where was all this deleted part moved to?

Duplicate - The new Dilatation class

pabloseleson · 2025-04-10T20:20:32Z

src/force/CabanaPD_PMB.hpp

+        auto model = _model;
+        const auto vol = particles.sliceVolume();
+        const auto nofail = particles.sliceNoFail();
+        auto theta = particles.sliceDilatation();


I assume we incorporate dilatation here for the densification model. Please note that the dilatation for densification should be the "plastic dilatation", i.e, the dilatation computed with the plastic stretch not the elastic stretch.

Yes, that is what's computed for the PMB. For the LPS we will need to consider this

pabloseleson · 2025-04-10T20:21:28Z

src/force/CabanaPD_PMB.hpp

+                // Else if statement is only for performance.
+                else if ( mu( i, n ) > 0 )
+                {
+                    const double coeff = model.forceCoeff( i, n, s, vol( j ) );


Where "forceCoeff" written?

In the models

pabloseleson · 2025-04-10T20:24:28Z

src/force/CabanaPD_PMB.hpp

+
+                model.thermalStretch( s, i, j );
+
+                model.updateDensity( i, theta( i ) );


Why do we update density here inside the force? The density is not needed for the force calculation.

BTW, I didn't see this density update for the NoFracture case.

Because we need to update density? There's no reason to do it in a separate loop

pabloseleson · 2025-04-10T20:31:02Z

src/force_models/CabanaPD_PMB.hpp

+                                            const double xi, const double vol,
+                                            const double ) const
+    {
+        return coeff * s * xi * vol;


Does this use the plastic stretch? I believe that should be s_p.

I believe you're referring to the variable name - up to you

pabloseleson · 2025-04-10T20:32:12Z

src/force_models/CabanaPD_PMB.hpp

+    {
+        // Update density using plastic dilatation.
+        // Note that this assumes zero initial plastic dilatation.
+        rho( i ) = rho0 * Kokkos::exp( theta_i ); // exp(theta_i - theta_i_0)


Does this use the plastic dilatation (as opposed the elastic dilatation)?

Again, the variable passed here is plastic, but maybe the variable name is what's confusing

new model form

…alization

src/CabanaPD_Particles.hpp

pabloseleson · 2025-04-16T16:35:18Z

src/force_models/CabanaPD_PMB.hpp

+    {
+        // Update density using plastic dilatation.
+        // Note that this assumes zero initial plastic dilatation.
+        rho_current( i ) = Kokkos::min( rho( i ) * Kokkos::exp( theta_i ),


I tried changing this to "rho_current( i ) = 10.0;" and I do not see that being output. So, I believe the reference density is output instead both for reference and current density.

… BC is not important

pabloseleson · 2025-06-19T23:16:25Z

src/force_models/CabanaPD_PMB.hpp

+    KOKKOS_INLINE_FUNCTION
+    auto currentC( const int i ) const
+    {
+        // Initial relative density for relative density factor (HARDCODED)


While we may consider inputing the initial relative density from the JSON file, I noticed an issue if the actual initial relative density equals D0

pabloseleson · 2025-06-19T23:17:19Z

examples/thermomechanics/hip_cylinder.cpp

+
+    // Impose separate density values for powder and container particles.
+    double W = inputs["wall_thickness"];
+    double D0 = inputs["powder_initial_relative_density"];


I call this D0, but it may not be the same as the D0 used in the PMB model for initial relative density due to the issue described there.

streeve requested a review from pabloseleson February 5, 2025 14:57

streeve self-assigned this Feb 5, 2025

streeve mentioned this pull request Feb 27, 2025

Consolidation physics #191

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5 tasks

pabloseleson reviewed Mar 21, 2025

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src/force/CabanaPD_ForceModels_PMB.hpp Outdated Show resolved Hide resolved

streeve added 5 commits April 2, 2025 17:42

Create Neighbor class and test;

508f397

stores list, handles iteration, and broken bonds

Separate dilatation from LPS forces

496a323

Initial draft of density update

bdad261

fixup: specific form of the PMB dilatation and density update

4b4c430

Add force for PMB with density update

9569501

streeve force-pushed the density_update branch from 85f805e to 9569501 Compare April 3, 2025 16:06

pabloseleson reviewed Apr 10, 2025

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pabloseleson and others added 5 commits April 10, 2025 18:58

Adding hip cylinder example

ba446a3

fixup: remove contact

3cfeeed

fixup: output density

e1b3481

Major changes for thermal-density evolution

b0fbe08

Updated HIP cylinder example;

2742c05

new model form

streeve force-pushed the density_update branch from 418deeb to 2742c05 Compare April 14, 2025 19:46

Revised density update - need to replace rho( i ) by rho0( i )

c9e11e3

streeve and others added 5 commits April 14, 2025 17:44

Add current density

c5ad0c2

Changes to example

34a4c04

Improvements to HIP example

0dcd7ae

Removed old files and added random number generator for density initi…

683716d

…alization

Added initial temperature

69d4b0e

pabloseleson reviewed Apr 16, 2025

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src/CabanaPD_Particles.hpp Outdated Show resolved Hide resolved

pabloseleson reviewed Apr 16, 2025

View reviewed changes

streeve and others added 3 commits April 16, 2025 13:37

fixup: wrong slice

f9006c3

Merge branch 'main' into density_update

d32b12e

Changes to HIP example

1dbe111

streeve force-pushed the density_update branch from f46d4b9 to 1dbe111 Compare April 16, 2025 21:06

streeve and others added 8 commits April 16, 2025 17:14

fixup: use solver particles for HIP example

7338850

fixup: unused

f6e80d4

fixup: should be a force update BC; only works for now since the temp…

6d084dc

… BC is not important

Initial version of running HIP example

70355f1

Add density dependent modulus

bbc4fde

fixup: unused

ec241c3

Add density dependent c

1c3034c

Added actual density dependence of elastic modulus based on literature

3eb7d34

pabloseleson reviewed Jun 19, 2025

View reviewed changes

pabloseleson added 4 commits June 25, 2025 18:36

Fixed issue with initial density profile when running on GPU

f2e0ed1

Added displacement constraints to avoid translation/rotation

5d54b54

Changes to HIP example

6882915

Added demonstration example of consolidation in a cubic RVE

482e2bd

		{
		fracture_type::prenotch( exec_space, particles, prenotch, _neigh_list );


		model.thermalStretch( s, i, j );

		model.updateDensity( i, theta( i ) );

Density update #186

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Density update #186

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streeve commented Feb 5, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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pabloseleson Apr 10, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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pabloseleson Apr 10, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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streeve commented Feb 5, 2025 •

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pabloseleson Apr 10, 2025 •

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pabloseleson Apr 10, 2025 •

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