5 Input file, initialization part
The initialization part contains initialization records and an
end_initia record
initialization
...
initialization
end_initia
The example below initializes a solid material
echo -yes
number_of_space_dimensions 2
materi_velocity
materi_strain_total
materi_stress
end_initia
The echo (always the first record),
number_of_space_dimensions (always the second record),
and end_initia record should be supplied always.
Use echo -yes to echo the input
and echo -no to not echo the input.
Use number_of_space_dimensions 1 for 1D problems, etc..
The records materi_velocity, materi_strain_total
and materi_stress create a velocity, strain and
stress field in the entire domain.
In the following sections,
all possible initialization records are discussed.
Most of these records create an unknown field, a
physical field like a temperature field or or a strain field,
over the computational domain.
5.1 echo switch (first record of initialization part)
If switch is -yes the input will be echoed.
If switch is -no the input will not be echoed.
This needs to be the first record.
5.2 number_of_space_dimensions number_of_space_dimensions
(second record of initialization part)
Set number_of_space_dimensions to 1 in 1D, etc..
You can also use the short name ndim if you prefer.
This needs to be the second record.
5.3 derivatives (third record of initialization part,
if specified)
If this record is included, the time derivative and the space derivatives
will be stored in the node_dof records.
This is only required for a limited number of models.
The model description will specify if
this derivatives initialization is needed.
5.4 condif_temperature
The temperature T is added to the node_dof records.
5.5 groundflow_velocity
The ground water flow velocity vig is added to the node_dof records.
Condition: the -groundflow differential group_type should be present.
5.6 groundflow_pressure
The pressure p is added to the node_dof records.
Condition: the -materi or -groundflow
differential group_type should be present.
5.7 materi_damage
The damage d is added to the node_dof records.
Also materi_velocity and materi_strain_total should be initialized.
5.8 materi_density
The density ρ is added to the node_dof records.
Now this density is used in the equations,
and the data item record materi_density in the data part
needs not to be specified.
The density is governed by the mass conservation law
where vj is the velocity in the direction of the
space coordinate xj.
Don't forget to initialize the density by specifying node_dof records.
Condition: the -materi differential group_type should be present.
5.9 materi_diffusion
The artificial diffusion c is added to the node_dof records.
It can be used in combination with materi_diffusion_minimum
to decide in an eulerian calculation where material is present and where not.
Initially set c to 0 at places where no material is
present, and set it to 1 at places where material is present.
The initialization needs to be done in the node_dof records.
The redistribution of diffusion is governed by the conservation law
where vj is the velocity in the direction of the space coordinate xj.
Condition: the -materi differential group_type should be present.
5.10 materi_displacement
The displacements u,v,w are added to the node_dof records.
If materi_displacement is initialized, then equations like the convection
and diffusion of heat equation or the ground water flow equation are evaluated over the
deformed volume, which is the sum of the nodal coordinates plus its displacements.
Also if materi_displacement is initialized, the total lagrange model will
be used in stress analysis.
Condition: also materi_velocity should be initialized because the displacement
follows from integration of the velocity.
5.11 materi_history_variables number_of_variables
Generic history variables which can e.g. be used in some
user supplied routines.
5.12 materi_maxwell_stress number_of_chains
Maxwell stress σ11m σ12m σ13m
σ22m σ23m σ33m
is added to the node_dof records.
The parameter number_of_chains should match
data item group_materi_maxwell_chains.
The number of maxwell stresses is 6 * number_of_chains.
Condition: the -materi differential group_type should be present.
5.13 materi_plasti_f
The plastic yield rule f is added to the node_dof records.
5.14 materi_plasti_f_nonlocal
The nonlocal plastic yield rule fn is added to the node_dof records.
See also: options_nonlocal.
5.15 materi_plasti_kappa
The plastic isotropic hardening parameter κ
is added to the node_dof records.
Condition: the -materi differential group_type should be present.
5.16 materi_plasti_rho
The plastic kinematic hardening vector
ρ11 ρ12 ρ13 ρ22
ρ23 ρ33 is added to the node_dof records.
See also group_materi_plasti_kinematic_hardening.
Condition: the -materi differential group_type should be present.
5.17 materi_strainenergy
The material strain energy 0.5 σij єijelas
is added to the node_dof records.
You can print or plot it to see where energy is stored after loading.
Also materi_stress and materi_strain_elasti should be initialised.
5.18 materi_strain_elasti
The elastic strain єklelas is added to the
node_dof records.
Condition: the -materi differential group_type should be present.
See also: materi_strain_total.
5.19 materi_strain_intergranular
The intergranular strain Sij is added to the node_dof records.
This can be used by hypoplasticity laws, see the theory section.
5.20 materi_strain_plasti
The plastic strain єklplas is added to the
node_dof records.
Condition: the -materi differential group_type should be present.
See also: materi_strain_total.
5.21 materi_strain_total
The total strain єkl is added to the node_dof records.
All strains are time integrals of the strain rates
for a specific material particle which happens to be present in the node.
Condition: the -materi differential group_type should be present.
5.22 materi_stress
The stresses σ11 σ12 σ13 σ22
σ23 σ33 are added to the
node_dof records.
Condition: the -materi differential group_type should be present.
5.23 materi_velocity
The velocities vi are added to the node_dof records.
Condition: the -materi differential group_type should be present.
5.24 materi_velocity_integrated
The integrated velocities vii are added to the node_dof records.
The integration of nodal velocities in fact results in displacements.
But asking for these integrated velocities doesn't activate automatically that the
calculation is done over the total deformed volume (as is the case when you
initialize materi_displacement), and not automatically a total lagrange model
is used in stress analysis.
Condition: also materi_velocity should be initialized because these are
necessary for calculation materi_velocity_integrated.
5.25 materi_void_fraction
The material void fraction f* is added to the node_dof records.
This is required for the group_materi_plasti_gurson model.
5.26 materi_work
The material second order work σij єij
is added to the node_dof records.
You can print or plot it to see where material instabilities are present.
A scalar unknown is added to the node_dof records.
The scalar is the residue in the differential equations.
Also derivatives should be initialized.
5.28 wave_scalar
Scalar in wave equation is node_dof records.
Condition: also wave_fscalar should be initialized
and the -materi differential group_type should be present.
5.29 wave_fscalar
The first time derivative in the wave equation is added to the node_dof records.
Condition: also wave_scalar should be initialized and
the -materi differential group_type should be present.
5.30 end_initia (last record of initialization part)