Description
The SPC entry defines sets of single-point constraints and enforced zero displacements. Time dependent enforced displacement must be enforced using the SPCD option.
Note that the SPC option does allow you to prescribe an initial non-zero displacement. In general, instantaneous non-zero boundary conditions applied in an explicit dynamics analysis introduce very strong shocks into the model and, if the magnitude of the displacement is large enough, can turn elements inside-out in the first time increment. If you absolutely must introduce a displacement at time zero into the mesh, use the SPCD option with an appropriate amplitude function (TABLED1, TABLED2 or TABLEH options).
Format
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| SPC1 | SID | C | G1 | G2 | G3 | G4 | G5 | G6 | |
| G7 | G8 | G9 | -etc.- |
Example
| SPC1 | 2 | 123 | 436 | 432 | 455 | 460 | 470 | ||
Alternate Form and Example
| SPC1 | SID | C | G1 | THRU | G2 |
| SPC1 | 2 | 246 | 2 | THRU | 122 |
| Field | Definition | Type | Default |
|---|---|---|---|
| SID | Identification number of single point constraint set. | Integer > 0 | Required |
| Gi | Grid point identification number(s). | Integer > 0; G1 < G2 | Required |
| C | Component number of global coordinate. (Up to six unique digits may be placed in the field with no embedded blanks.) | 1 ≤ Integers ≤ 6 | Required |
Remarks
- Note that enforced displacements are not available via this entry.
- Single-point constraint sets must be selected in the Case Control Section (SPC = SID) to be used.
- If the alternate form is used, points in the sequence G1 through G2 are not required to exist. Points that do not exist will be skipped.