/MAT/LAW72 (HILL_MMC)
Block Format Keyword This law describes the anisotropic Hill material with a modified Mohr fracture criteria. This law is available for shell and solid.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
/MAT/LAW72/mat_ID/unit_ID or /MAT/HILL_MMC/mat_ID/unit_ID | |||||||||
mat_title | |||||||||
E | v | ||||||||
n | F | G | |||||||
H | N | L | M | ||||||
C1 | C2 | C3 | m | Dc |
Definitions
Field | Contents | SI Unit Example |
---|---|---|
mat_ID | Material identifier. (Integer, maximum 10 digits) |
|
unit_ID | Unit Identifier. (Integer, maximum 10 digits) |
|
mat_title | Material title. (Character, maximum 100 characters) |
|
Initial density. (Real) |
||
E | Initial Young's modulus. (Real) |
|
v | Poisson's ratio. (Real) |
|
Initial yield stress. Default = 1030 (Real) |
||
Initial plastic strain. (Real) |
||
n | Exponent for the isotropic function for the swift hardening:
It is also used as an exponent in the MMC failure equations. 2 (Real) |
|
F, G, H, L, M, N | Six
HILL Materials anisotropic
parameters. (float) |
|
C1 | First parameter for MMC fracture model. (Real) |
|
C2 | Second parameter for MMC fracture model. (Real) |
|
C3 | Third parameter for MMC fracture model. (Real) |
|
m | Exponent for the softening function. 3 (Real) |
|
Dc | Critical damage.
(Real) |
Example (Metal)

Figure 1.
#RADIOSS STARTER
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/UNIT/1
unit for mat
g mm ms
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#- 2. MATERIALS:
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/MAT/LAW72/1/1
Metal
# RHO_I
0.0028
# E nu
200E+3 0.3
# Sig0 Eps0 n F G
1276 1.63E-3 0.265 0.5 0.5
# H N L M
0.5 1.5 0 0
# C1 C2 C3 m Dc
0.12 720 1.095 0.5 1.1
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#ENDDATA
/END
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
Comments
- 3D
equivalent Hill stress:
(1) For shell element, take:(2) - MMC
fracture criteria:
(3) - Anisotropic 3D model
(4) While,
is Lode angle
with Lode angle parameter
is the third invariant of the deviatoric stress.
is stress triaxiality with
- 2D Anisotropic Model
(5) with,(6) (7) (8)
- Anisotropic 3D model
- Fracture and damage
with MMC fracture criteria:
- When D = 1: fracture initiate
- By 1 < D <
Dc: the yield stress is multiplied by
softening function
to reduce the deformation resistance.
with
- If D ≥ Dc, the element is deleted.
- The exponent m is used to describe the softening behavior. It is
recommended to use m > 0.
If 0 < m < 1, then the softening curve is convex.
If m > 1, then the softening curve is concave. The softening is between and . Once the plastic strain is reached (in this case ), then the element is deleted.
Figure 2.
Figure 3.
- It is possible to
display user variables in animation files (with Engine /ANIM/Eltyp/Restype) and in Time history file (with Starter /TH/SHEL and /TH/BRIC):
- USER1: Plastic strain
- USER2: Damage value