/MAT/LAW51 (MULTIMAT)
Block Format Keyword Up to four material laws can be defined: elasto-plastic solid, liquid, gas and detonation products. The material law is based on a diffusive interface technique to get sharper interfaces between submaterial zone (/ALE/MUSCL in Radioss Starter Input).
It is not recommended to use this law with Radioss single precision engine.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
/MAT/LAW51/mat_ID/unit_ID | |||||||||
mat_title | |||||||||
Blank | |||||||||
Iform |
Formulation Types
Formulation | Number of Sub-materials | Plasticity | Explosive |
---|---|---|---|
Iform = 0 | 3 | -- | -- |
Iform = 1 | 3 | Johnson-Cook | -- |
Iform = 10 | 4 | Johnson-Cook | Jones-Wilkins-Lee |
Iform = 11 | 4 | Johnson-Cook Drücker-Prager |
Jones-Wilkins-Lee |
Iform = 12 | 5 | Johnson-Cook Drücker-Prager |
Jones-Wilkins-Lee |
Outlet formulation (Iform=3) is obsolete since 2018.0 version. It is replaced by new Non-Reflecting-Frontier (Iform = 6)
Modeling Technique with Polynomial EOS
Material Hypothesis | Output | Modeling | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
C0 | C1 | C2 | C3 | C4 | C5 | E0 | Pext | Pmin | ||
Perfect gas (Example 43) | ||||||||||
-P0 | P0 | |||||||||
Water (Linear EOS) | P0 | |||||||||
P0 | -P0 | |||||||||
Elastic Solid (Linear EOS) | P0 | |||||||||
P0 | ||||||||||
Mie-Gruneisen constant |
K1 | E0 | P0 | |||||||
Mie-Gruneisen linear
|
K1 | E0 | P0 |
- Total pressure and total energy formulation
- Relative pressure and total energy formulation
- Total pressure and relative energy formulation
- Relative pressure and relative energy formulation
- P0
- Initial total pressure
- E0
- Initial total energy
- Perfect gas constant
- E
- Young's modulus
- Poisson coefficient
- Gruneisen's gamma
- Coefficient for first order volume correction to the Gruneisen gamma
- c
- Speed of sound
- Initial density
- S
- Linear Hugoniot slope coefficient
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.
- Time step for ALE material laws can be tune with Engine card /DT/ALE; by default, scale factor on time step is 0.5
- This law can emulate /MAT/LAW37 (BIPHAS) (liquid and gas mixture) with less diffusion. It can also replace /MAT/LAW20 (BIMAT) in 2D analysis since /MAT/LAW51 is compatible with QUAD elements.
- /MAT/LAW51 (MULTIMAT) is based on the equilibrium between
each material present inside the element. Radioss
computes and outputs a relative pressure
. At each cycle:
User can deduce total pressure using output value and input parameter :
(5) - Tetra 4 elements can be used for this law, but BRICK elements are currently highly recommended for better numerical solution in ALE.