MATX33
Bulk Data Entry Defines additional material properties for visco-elastic plastic foam material for geometric nonlinear analysis.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
MATX33 | MID | KA | TID | FSCALE | P0 | PHI | EPSV0 | ||
A | B | C | E1 | E2 | ET | ETAC | ETAS |
Example
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
MAT1 | 133 | 0.11 | 0.11 | 9.92E-07 | |||||
MATX33 | 133 | 0 |
Definitions
Field | Contents | SI Unit Example |
---|---|---|
MID | Material ID of the
associated MAT1. 1 No default (Integer > 0) |
|
KA | Analysis type flag.
(Character) |
|
TID | Identification number of
TABLES1 entry that defines the yield stress
versus volumetric strain curve. If defined, versus is read from input of the curve. No default (Integer > 0) |
|
FSCALE | Scale factor for stress in
yield curve. Default = 1.0 (Real) |
|
P0 | Initial air pressure.
4 Default = 0.0 (Real) |
|
PHI | Ratio of foam to polymer
density. Default = 0.0 (Real) |
|
EPSV0 | Initial volumetric
strain. Default = 0.0 (Real) |
|
A | Yield parameter. Default = 0.0 (Real) |
|
B | Yield parameter. Default = 1.0 (Real) |
|
C | Yield parameter. Default = 1.0 (Real) |
|
E1 | Coefficient for Young's
modulus update. No default (Real) |
|
E2 | Coefficient for Young's
modulus update. No default (Real) |
|
ET | Tangent modulus. No default (Real ≥ 0) |
|
ETAC | Viscosity coefficient in
pure compression. Default = 1.0 (Real ≥ 0) |
|
ETAS | Viscosity coefficient in
pure shear. Default = 1.0 (Real ≥ 0) |
Comments
- The material identification number must be that of an existing MAT1 Bulk Data Entry. Only one MATXi material extension can be associated with a particular MAT1.
- MATX33 is only applied in geometric nonlinear analysis subcases which are defined by ANALYSIS = EXPDYN. It is ignored for all other subcases.
- This material can be used only with solid elements, typically used to model low density, closed cell polyurethane foams such as impact limiters.
- The air pressure is computed
as:
Pair = * / (1+ - ),
with = 0 + V/V0 - 1
Where,- Volumetric strain
- Porosity
- Initial air pressure
- 0
- Initial volumetric strain
The volumetric strain < 0 in compression.
- TID is blank or zero,
then
= A + B(1+ C ),
with = V/V0 - 1 = / - 1 = - /(1+ )
- The Young's modulus used in the
calculation is:
(1) This material assumes NU = 0 no matter what is defined on the corresponding MAT1. Hence, G = 0.5 * E.
- This card is represented as an extension to a MAT1 material in HyperMesh.