pycbg.preprocessing.Materials¶

class pycbg.preprocessing.Materials¶

Create materials for particle sets.

materials¶

Each element is a dictionnary containing a material’s parameters. The index of a material is his id.

Type: list of dict

pset_ids¶

The element i of this list is the id (or list of ids) of the particle set made of the material defined in materials[i].

Type: list of (ints or list of ints)

Notes

Due to (probably) a bug in CB-Geo MPM, materials should be created in the same order than the corresponding particle sets (so particle sets and materials have the same id).

Examples

Creating two materials for two particle sets :

>>> mesh = Mesh((1.,1.,1.), (1,1,1))
>>> particles = Particles(mesh, 2)
>>> entity_sets = EntitySets(mesh, particles)
>>> lower_particles = entity_sets.create_set(lambda x,y,z: x<.5, typ="particle")
>>> upper_particles = entity_sets.create_set(lambda x,y,z: x>=.5, typ="particle")
>>> materials = Materials()
>>> materials.create_MohrCoulomb3D(pset_id=lower_particles, density=750,
...                                                         youngs_modulus=5.26e7,
...                                                         poisson_ratio=.3,
...                                                         friction=36.,
...                                                         dilation=0.,
...                                                         cohesion=1.,
...                                                         tension_cutoff=1.,
...                                                         softening=False)
>>> materials.create_Newtonian3D(pset_id=upper_particles, density=1.225,
...                                                       bulk_modulus=1.42e5,
...                                                       dynamic_viscosity=1.81e3)
>>> materials.pset_ids
[0, 1]

__init__()¶

Methods

`__init__`
`create_LinearElastic3D`	Create LinearElastic3D material.
`create_MohrCoulomb3D`	Create MohrCoulomb3D material, as specified by CB-Geo MPM documentation.
`create_Newtonian3D`	Create Newtonian3D material, as specified by CB-Geo MPM documentation.

create_LinearElastic3D(pset_id=0, density=1000.0, youngs_modulus=50000000.0, poisson_ratio=0.3)¶

Create LinearElastic3D material.

Parameters

pset_id (int or list of ints) – Particle set id that will be made of this material
density (float) – Density of the material (\(kg/m^3\)). Default is 1000 \(kg/m^3\).
young_modulus (float) – Young’s modulus of the material (\(Pa\)). Default is 50 \(MPa\).
poisson_ratio (float) – Poisson’s ratio of the material. Default is 0.3 .

create_MohrCoulomb3D(pset_id=0, density=1000.0, youngs_modulus=50000000.0, poisson_ratio=0.3, friction=36.0, dilation=0.0, cohesion=0.0, tension_cutoff=0.0, softening=False, peak_pdstrain=0.0, residual_pdstrain=0.0, residual_friction=13.0, residual_dilation=0.0, residual_cohesion=0.0)¶

Create MohrCoulomb3D material, as specified by CB-Geo MPM documentation.

Parameters

pset_id (int or list of ints) – Particle set id that will be made of this material
density (float) – Density of the material (\(kg/m^3\)). Default is 1000 \(kg/m^3\).
young_modulus (float) – Young’s modulus of the material (\(Pa\)). Default is 50 \(MPa\).
poisson_ratio (float) – Poisson’s ratio of the material. Default is 0.3 .
friction (float) – Friction angle of the material (\(^\circ\)). Default is 36 \(^\circ\).
dilation (float) – Dilation angle of the material (\(^\circ\)). Default is 0 \(^\circ\).
cohesion (float) – Cohesion in the material (\(Pa\)). Default is 0 \(Pa\).
tension_cutoff (float) – Tension strength of the material (\(Pa\)). Default is 0 \(Pa\).
softening (bool, optional) – Enable softening option. If True, one has to set peak_pdstrain, residual_pdstrain, residual_friction, residual_dilation and residual_cohesion. Default is False.
peak_pdstrain (float, optional) – Start point of strain softening. Default is 0.
residual_pdstrain (float, optional) – End point of strain softening. Default is 0.
residual_friction (float, optional) – Residual friction angle (\(^\circ\)). Default is 13 \(^\circ\).
residual_dilation (float, optional) – Residual dilation angle (\(^\circ\)). Default is 0 \(^\circ\).
residual_cohesion (float, optional) – Residual cohesion (\(Pa\)). Default is 0 \(Pa\).

create_Newtonian3D(pset_id=0, density=1.225, bulk_modulus=142000.0, dynamic_viscosity=1.81e-05)¶

Create Newtonian3D material, as specified by CB-Geo MPM documentation.

Parameters

pset_id (int or list of ints) – Particle set ids that will be made of this material
density (float, optional) – Density of the material (\(kg/m^3\)). Default is 1.225 \(kg/m^3\).
bulk_modulus (float, optional) – Bulk modulus of the material (\(Pa\)). Default is 142 \(kPa\).
dynamic_viscosity (float, otpional) – Dynamic viscosity of the material (\(Pa.s\)). Default is 18.1 \(\mu Pa.s\)

Notes

Defaults correspond to air’s properties.