/MAT/LAW10 (DPRAG1)
Block Format Keyword This law, based on an extended Drucker-Prager yield criteria, is used to model materials with internal friction such as rock-concrete.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
/MAT/LAW10/mat_ID/unit_ID or /MAT/DPRAG1/mat_ID/unit_ID | |||||||||
mat_title | |||||||||
E | |||||||||
A0 | A1 | A2 | Amax | ||||||
Definition
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 | Young's
modulus. (Real) |
|
Poisson's
ratio. (Real) |
||
A0 | Yield criteria
coefficient. (Real) |
|
A1 | Yield criteria
coefficient. (Real) |
|
A2 | Yield criteria
coefficient. (Real) |
|
Amax | Yield criteria limit (von
Mises limit). (Real) |
|
Minimum
pressure. Default = -1030 (Real) |
Example (Concrete)
#RADIOSS STARTER
/UNIT/1
unit for mat
g cm mus
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#- 2. MATERIALS:
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/MAT/LAW10/1/1
Concrete
# RHO_I
2.4
# E Nu
.576 .25
# A0 A1 A2 Amax
9.72E-10 4.32E-5 .48 .013
# P_min
-1E-20
/EOS/COMPACTION/1/1
Concrete EOS
# C0 C1 C2 C3
0.0 0.256 0.256 1
# MUMIN MUMAX BUNL
0.0 0.44 0.115
# PSH RHO0
0 2.40
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#ENDDATA
Comments
- Original Drucker-Prager
yield criterion has a linear pressure dependency.
Radioss is using the extended Drucker-Prager yield criteria whose pressure dependency is nonlinear.
- Extended Drucker-Prager
yield criteria can be compared with Mohr-Coulomb criteria.
An extended Drucker-Prager yield criterion can be fitted from Mohr-Coulomb parameters:
- Cohesion parameter
- Angle of internal friction
For this purpose, parameters must be defined as:(1) - Modeling Type
- Parameters
- Circumscribed Drucker-Prager criteria
- Middle Circle
- Inscribed Drucker-Prager criteria
- /MAT/LAW21 is also based on an extended Drucker-Prager yield criteria but pressure evolution can be described with user functions.
- Young's modulus E and Poisson’s ratio are used to determined shear modulus G which is required for sound speed calculation in solid materials.
- Starter checks the yield parameters A0, A1, and A2 and warns you in case of an unexpected situation.