Effect of Shell Shape and Formulation on Output
Effect of shell shape and formulation on output
Thick shells in Ansys LS-DYNA may be hexahedra or extruded triangles. They may have a single integration point on plan, or be fully integrated. They may have from 1 to <n> integration points through their thickness.
However, like thin shells:
| On plan: | thick shells only report results at their centre; |
| In elevation: | thick shells only report results at <maxint> points through their thickness. |
( <maxint> is on the *DATABASE_EXTENT_BINARY card, and is explained in Controllable contents of the complete state file
In most respects thick shells are like thin shells, and you are encouraged to read Description of shell output which describes some of the pitfalls of using them. This will not be repeated here.
For thick shells, if <maxint> = 3, the order of output is middle, bottom, top. For any other value of <maxint> the order of output is always #1, #2, #3 ... #nip, i.e. from bottom to top.
NOTE: For thick shells, ELFORM=1, if <NIP> on the *SECTION card = 2 then Ansys LS-DYNA switches it to 3 integration points. Similarly, if <NIP> = 4 it is switched to 5.
To summarise the order of output for Thick Shells is:
| MAXINT value | Surface output order |
| 3 | Always MIDDLE, BOTTOM, TOP |
| Anything else | In order from BOTTOM to TOP |
If a ZTF file is present, D3PLOT will know how many integration points a shell has and will therefore be able to determine the correct value to read for a selected surface, based on the rules above.