Iform = 1
Block Format Keyword This material is able to handle up to three elasto plastic materials (solid, liquid, or gas). The material law is based on a diffusive interface technique.
- P
- Positive for a compression and negative for traction.
Where, means that the EOS is linear for an expansion and cubic for a compression.
By default process is adiabatic . To enable thermal computation, refer to 6.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
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/MAT/LAW51/mat_ID/unit_ID | |||||||||
mat_title | |||||||||
Blank | |||||||||
Iform |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
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Pext |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
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(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
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Definition
Field | Contents | SI Unit Example |
---|---|---|
mat_ID | Material identifier. (Integer, maximum 10 digits) |
|
unit_ID | Unit Identifier. (Interger, maximum 10 digits) |
|
mat_title | Material title. (Character, maximum 100 characters) |
|
Iform | Formulation flag. (Integer) |
|
Pext | External pressure. 2 Default = 0 (Real) |
|
Kinematic viscosity shear
. 3 Default = 0 (Real) |
||
Kinematic viscosity (volumetric),
which corresponds to
Stokes Hypothesis. 3 Default = 0 (Real) |
||
Initial volumetric fraction. 4 (Real) |
||
Initial density. (Real) |
||
Initial energy per unit
volume. (Real) |
||
Hydrodynamic cavitation pressure. 5 If fluid material ( ), then default = . If solid material ( ), then default = -1e30. (Real) |
||
Initial pressure. (Real) |
||
Hydrodynamic coefficient. (Real) |
||
Hydrodynamic coefficient. (Real) |
||
Hydrodynamic coefficient. (Real) |
||
Hydrodynamic coefficient. (Real) |
||
Hydrodynamic coefficient. (Real) |
||
Elasticity shear modulus.
(Real) |
||
Plasticity yield stress. (Real) |
||
Plasticity hardening
parameter. (Real) |
||
Plasticity hardening exponent. Default = 1.0 (Real) |
||
Strain rate coefficient.
Default = 0.00 (Real) |
||
Reference strain rate. If , no strain rate effect (Real) |
||
Temperature exponent. Default = 1.00 (Real) |
||
Initial temperature. Default = 300 K (Real) |
||
Melting temperature.
Default = 1030 (Real) |
||
Maximum temperature. Default = 1030 (Real) |
||
Specific heat per unit of volume. 7 (Real) |
||
Failure plastic strain. Default = 1030 (Real) |
||
Plasticity maximum stress. Default = 1030 (Real) |
||
Thermal conductivity coefficient 1. 8 (Real) |
||
Thermal conductivity coefficient 2. 8 (Real) |
▸Example
Comments
- Numerical diffusion can be improved using the second order method for volume fraction convection, /ALE/MUSCL. The previous /UPWIND used to limit diffusion is now obsolete.
- Radioss
computes and outputs a relative pressure
.
(6) However, total pressure is essential for energy integration ( ). It can be computed with the external pressure flag Pext.
leads to .
This means that if Pext = 0, the computed pressure is also the total pressure: .
- Kinematic viscosities are global and is
not specific to each material. It allows computing
viscous stress tensor:
(7) Where,- Cinematic shear viscosity flag
- Cinematic volumetric viscosity flag
- Volumetric fractions enable the sharing
of elementary volume within the three different
materials.
For each material must be defined between 0 and 1.
Sum of initial volumetric fractions must be equal to 1.
For automatic initial fraction of the volume, refer to the /INIVOL card.
-
flag is the minimum
value for the computed pressure
. It means that total
pressure is also bounded to:
(8) For fluid materials and detonation products, must remain positive to avoid any tensile strength so must be set to .
For solid materials, default value = 1e-30 is suitable but may be modified.
- Heat contribution is computed only if the
thermal card is associated to the material law
(/HEAT/MAT).In this case, and the parameters for thermal diffusion are read for each material:
(9) For solids and liquids, for perfect gas:
- The temperature evolution in the Johnson-Cook model is computed with the flag , even if the thermal card (/HEAT/MAT) is not defined.
- Thermal conductivity,
, is linearly dependent
on the temperature:
(10) - Material tracking is possible through
animation
files:
/ANIM/BRIC/VFRAC (All material volumetric fractions)