Description
Specifies stress-dependent material properties. This entry is used if a MAT1 entry is specified with the same MID.
Format
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| MATS1 | MID | TID | H | YF | HR | LIMIT1 | LIMIT2 | ||
| DILATION | YTYPE |
Example
| MATS1 | 25 | 100 | 1.E5 | 1 | 1 | 2.E4 |
| Field | Definition | Type | Default |
|---|---|---|---|
| MID | Identification number of a MAT1, MAT2, MAT8, MAT9, or MAT12 entry. | Integer > 0 | Required |
| TID | Identification number of a TABLES1, TABLESR or TABLEST entry. If H is given, then this field must be blank. See Remark 2. | Integer ≥ 0 or blank | |
| YF |
Yield function criterion, selected by one of the following values: 1 = von Mises 4 = Drucker-Prager |
Integer | von Mises |
| H | Work hardening slope (slope of stress vs. plastic strain) in units of stress. For more than a single slope in the plastic range, the stress-strain data must be supplied on a TABLES1 entry referenced by TID, and this field must be blank. See Remark 1. | Real | |
| HR |
Hardening rule, selected by one of the following values: 1 = Isotropic |
Integer | Isotropic |
| LIMIT1 | Initial yield point. Y1. Ignored if TID ≠ 0 | Real | 0.0 |
| LIMIT2 | Internal friction angle (measured in degrees) for the Drucker-Prager yield criteria. | Real | 0.0 |
| DILATION | Dilation angle (measured in degrees) for the Drucker-Prager yield criteria. | Real < 71.5 | 0.0 |
| YTYPE | Yield curve type for the Drucker-Prager yield criteria:
YTYPE = 1 Compression YTYPE = 2 Tension YTYPE = 3 Shear |
Integer > 0 | 1 |
Remarks
-
Either the table identification TID or the work hardening slope H may be specified, but not both. If the TID is omitted, the work hardening slope H must be specified unless the material is perfectly plastic. The plasticity modulus (H) is related to the tangential modulus (ET) by
where E is the elastic modulus and
is the slope of the uniaxial stress-strain curve in the plastic region. See Figure 1.
Figure 1: Stress-Strain Curve Definition When H is Specified in Field 5.
-
If TID is given, TABLES1 entries (Xi, Yi) of stress-strain data (εk, Yk) must conform to the following rule: the curve must be defined in the first quadrant. The first point must be at origin (X1 = 0, Y1 = 0) and the second point (X2, Y2) must be at the initial yield point (Y1 or 2c) specified on the MATS1 entry. The slope of the line joining the origin to the yield stress must be equal to the value of E.