how FEAP recognize if the element type is quadrilateral or tetrahedral element?

[fortran88]

Feap admin,

I am now trying to write 'Elmtnn', which uses both quadrilateral (2D) and tetrahedral (3D).

and,
The input file has

Elements
       1   0   2        1        2        3        4

then, which type of element is recognized by FEAP, a quadrilateral or tetrahedral?

[FEAP_Admin]

It will figure that out by the material set number.  In your case it will look at MATE 2 and the USER line under to figure out what to do.

[Prof. R.L. Taylor]

In past versions of FEAP the difference between a 4-node quad and a 4-node tet was either by the problem dimension "ndm" or the different element types (e.g., a shell vs a solid).

The version 8.5 of FEAP is starting the process to set element types in the node connection array (usually IX(nen1,numel) in most arrays or just IX(*) in and element module.  The entry ix(nen+7,n)  or ix(nen+7) stores the element type.  Currently,
this may be set on the ELEMent record, which has new options:

      ELEMent  NODES=nel  TYPE=<LINE,TRIAngle,QUAD,TETR,HEXA,WEDGe,PYRAmid,POINt, ...>
these set the IX(nen+7 ..) to          -1      -2          -3      -4     -5       -6         -7         -8

The entries in the ix are also used for both IgA and VEM element forms too.

The type of element is available in the 'elmtnn.f' modules using the include: include 'eldata.h' as variable 'eltyp'

At present only VEM and IgA elements are forcing use of the parameter.  Users can, however, use them if necessary.