cb-geo / mpm

CB-Geo High-Performance Material Point Method

CB-Geo webpage

Krishna Kumar

Based on So Simple Theme

Pre-requisites

• ruby > 2.0

• ruby-devel

• rubygem-bundler

• zlib zlib-devel zlib-static

Getting Started

• bundle update

• bundle exec jekyll build --incremental

• bundle exec jekyll serve --watch

• Point your browser to localhost:4000

HTML-Proofer test

• set -e
• bundle exec jekyll build --drafts
• bundle exec htmlproof ./_site

mpm's Issues

Compute local coordinates of a particle

• The local coordinates of a particle are required to transfer information between the nodes and the particles.

Frictional boundary

Handle friction boundary

Assign particle properties to nodes

• Assign:

• mass
• momentum
• force
• velocity

from particles to nodes

MPM Node class

• Mass of soil / water

• Force vector

• Velocity vector

• Momentum vector

• Acceleration vector

Support docker build

Check inhedron indices for 2D shape functions

• Write tests for inhedron indices.

Learning document

Hi all,
Is there any learning document on the MPM code? For example, the example files, how to running and visual the results.
Thanks a lot!
Best regards,
Henry

how to use it?

Dear all,
How to use it? Is there any detail document or user manual?
Thanks a lot!

Material point class

• id

• reference location

• properties

https://github.com/geodynamics/aspect/blob/master/include/aspect/particle/particle.h

Cundall damping

References

• MPM modelling of landslides in brittle and unsaturated soils.
• Two-phase dynamic analysis by material point method for implementation of damping.

Doxygen fails to document code in template implementation

• Document in .h not in (.cc / *.tcc) or at least in addition to the header file

MPM explicit class

A super class that calls algorithms in the meshes

Check if a point is inside a hedron or a polygon

• Using a volume summation of tetrahedron / triangles in 2D to check if a point is inside a given volume or not.
• Hexahedron for 3D: Made of sub-tetrahedrons
• Quadrilateral for 2D: Made of sub-triangles

Template specialisation with an integer doesn't work

Template specialisation with the dimension parameter doesn't work, it always calls the 3D case, even for the 2D case. The following case should call 2D, instead the call is to the 3D function

template <>
mpm::Cell<2> function(){ std::cout << "2D\n";}

template <>
mpm::Cell<2> function(){ std::cout << "3D\n";}

Expected behaviour for

auto cell = std::make_shared<mpm::Cell<3>>()
cell->function();

is to print 2D instead prints 3D.

Needs template specialisation done through SFINAE

Material Base

• Material ID

• Basic material properties

• Compute stresses and strains

Particle handler

This class manages the storage and handling of particles. It provides the data structures necessary to store particles efficiently, accessor functions to iterate over particles and find particles, and algorithms to distribute particles in parallel domains.

https://github.com/geodynamics/aspect/blob/master/include/aspect/particle/particle_handler.h

Implement USL algorithm

• Use USL

Particle unit testing

• Catch framework to test particle classes

• Particle

• ParticleHandler

• ParticleIterator

• PropertyPool

• ParticleAccessor

Node multiphase properties

Use Eigen::VectorXd to store properties, and an unsigned to store degrees of freedom.

Cam Clay

Depends on #6

• Implementation

• Unit testing

Paraview VTK visualisation

• Compressed binary vtu files

Compute internal forces at nodes

Material factory

Material factory

Mohr Coulomb

Depends on #6

• Implementation

• Unit testing

Compute volume of a cell

• Compute the volume of a hexahedron and a 2D area

https://encrypted.google.com/url?q=https://arc.aiaa.org/doi/pdf/10.2514/3.9013&sa=U&ved=0ahUKEwj17dnl6InZAhWJKMAKHfoFDOcQFggTMAA&usg=AOvVaw1BA6DTuSvdL_t46KjpqDgT

Bingham fluid

Depends on #6

• Implementation

• Unit testing

Property pool

This class manages the memory space in which particles store their properties. Because this is dynamic memory and every particle needs the same amount it is more efficient to let this be handled by a central
manager that does not need to allocate/deallocate memory every time a particle is constructed/destroyed.

https://github.com/geodynamics/aspect/blob/master/include/aspect/particle/property_pool.h

Support CI with CircleCI

Unit test MPM node class

MPM Particle properties

Add particle properties such as mass, stress, etc

Unit test boundaries

• Traction

• Friction

• Loading

• General boundary constraints

Cell MPM algorithm

• MPM Explicit algorithm function at cell level

Unit test mpm mesh class

MPM Mesh class

• Cell containers

• Node containers

• Particle containers

Compute B matrix in Quadrilateralshapefn class

Damping validation test

See section 4.10 in Two-phase dynamic analysis by material point method for implementation of damping for validation of damping in MPM

Particle iterator

A class that is used to iterate over particles. Together with the ParticleAccessor class this is used to hide the internal implementation of the particle class and the particle container.

https://github.com/geodynamics/aspect/blob/master/include/aspect/particle/particle_iterator.h

Weighted mesh partititoning

ParMETIS looks like an ideal candidate for mesh partitioning

Other candidates

MOAB: https://bitbucket.org/fathomteam/moab.git
Zoltan

Unit testing cell

Node class

• Node base class

• Node handler class with iterator

Cell / Grid

https://github.com/dealii/dealii/tree/master/include/deal.II/grid

• Cell

• Cell iterator

• Grid

• Grid across multiple processors

Traction

Apply traction on material points

Include Dealii as FE base library

MPM element test

• Single element test

HDF5 support

• Write to HDF5 for particle

Fix serialize/de-serialize in particles

• The boost serialization function requires a template argument. However, the base class Particle_Base is an abstract base class, and it is not possible to have virtual base class member functions to be templatised.

Template specialisation issue in shape functions

Can't specialise shape functions as <3, 8> and <3,20> it is always <unsigned, unsigned>.

Particle accessor

https://github.com/geodynamics/aspect/blob/master/include/aspect/particle/particle_accessor.h

Isotropic Linear Elastic

Isotropic linear elastic model: https://github.com/cb-geo/mpm-3d/tree/master/cartesian/material/isotropicLinearElastic

Write test functions for information mapping

Write test functions for velocity, force and momentum mapping to nodes