MATX21
Bulk Data Entry Defines additional material properties for Rock-Concrete material for geometric nonlinear analysis.
This law is based on the Drücker-Prager yield criteria and is used to model materials with internal friction such as rock-concrete. The plastic behavior of these materials is dependent on the pressure in the material. This law is only applicable to solid elements.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
MATX21 | MID | A0 | A1 | A2 | AMAX | ||||
TPID | KT | FSCAL | PMIN | B | MUMAX | PEXT |
Example
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
MAT1 | 102 | 3.1E10 | 0.33 | 1000.0 | |||||
MATX21 | 102 | 3 | |||||||
1 | 1E10 |
Definitions
Field | Contents | SI Unit Example |
---|---|---|
MID | Material ID of the
associated MAT1. 1 No default (Integer > 0) |
|
A0 | Coefficient. (Real) |
|
A1 | Coefficient. (Real) |
|
A2 | Coefficient. (Real) |
|
AMAX | von Mises limit. Default = 1030 (Real > 0) |
|
TPID | Identification number of a
TABLES1 that defines the volumetric strain
versus pressure function. No default (Integer > 0) |
|
KT | Tensile bulk
modulus. Recommended to set equal to 1/100 of unloading bulk modulus. Must be positive. (Real > 0.0) |
|
FSCAL | Scale factor for pressure
function. Default = 1.0 (Real) |
|
PMIN | Minimum
pressure. Default = -1030 (Real) |
|
B | Unloading bulk
modulus. Recommended to set equal to the initial slope of function describing . Must be positive. (Real > 0.0) |
|
MUMAX | Maximum compression
volumetric strain. (Real) |
|
PEXT | External
pressure. Required if relative pressure formulation is used. In this specific case, yield criteria and energy integration require the value of total pressure. Default = 0.0 (Real) |
Comments
- The material identification number must be that of an existing MAT1 Bulk Data Entry. Only one MATX21 material extension can be associated with a particular MAT1.
- MATX21 is only applied in geometric nonlinear analysis subcases which are defined by ANALYSIS=EXPDYN. It is ignored for all other subcases.
- Hydrodynamic behavior is given by a
user-defined function
.Where,
- Pressure in the material
- Volumetric strain
- Drücker-Prager yield criteria uses a
modified von Mises yield criteria to incorporate the effects of pressure for
massive structures:
(1) Where,- Second invariant of deviatoric stress
- Pressure
- , , and
- Material coefficients
means that the yield criteria is von Mises ( ). - This card is represented as an extension to a MAT1 material in HyperMesh.