The tangent stiffness matrix must be calculated for implicit materials.
Any list of material models available for implicit
tends to become outdated very quickly.
Aside from running a test case (a single element model would suffice) to
see if you get an error or warning message, the alternative is for someone at LSTC to examine
the source code and see if a particular element formulation/material combination
is currently supported in implicit. Future implementation is generally customer-driven.
In the data statement matimp below, an entry of zero means that the corresponding
material number is unsupported by implicit.
For example, the table reveals that material types 8, 39, 86, and so on,
are unsupported by the implicit solver.
If the data statement matimp contains the material number instead of zero,
then the corresponding material is supported for implicit calculations, but
that doesn't guarantee that the material implementation for implicit is
completely robust or comprehensive. Simply put, the implementation of some
material models for implicit makes use of simplifying assumptions such that the
tangent stiffness is approximated.
When use of an unsupported material is attempted in an implicit simulation,
an error message of the following format is written ...
1 5x,'*********************************************************'/
2 5x,'* *'/
3 5x,'* - FATAL ERROR - *'/
4 5x,'* *'/
5 5x,'* Material type ', i8 ,' is not supported *'/
6 5x,'* by the implicit solver *'/
7 5x,'* *'/
8 5x,'*********************************************************')
or in the case of *MAT_224_GYS,
1 5x,'*********************************************************'/
2 5x,'* *'/
3 5x,'* - FATAL ERROR - *'/
4 5x,'* *'/
5 5x,'* Material *MAT_224_GYS is not supported *'/
6 5x,'* by the implicit solver *'/
7 5x,'* *'/
8 5x,'*********************************************************')
Table of materials supported by implicit ( "data matimp" in dyn4a.F)
as it appears in the R10.0.0 source code...
data matimp/
. 1, 2, 3, 4, 5, 6, 7, 0, 9, 10,
1 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
2 21, 22, 23, 24, 25, 26, 27, 28, 29, 30,
3 31, 32, 33, 34, 35, 36, 37, 38, 0, 40,
4 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
5 51, 52, 53, 54, 55, 0, 57, 58, 59, 60,
6 61, 62, 63, 64, 65, 66, 67, 68, 69, 70,
7 71, 72, 73, 74, 75, 76, 77, 78, 79, 80,
8 81 , 82, 83, 84, 85, 0, 87, 88, 89, 0,
9 91, 92, 93, 94, 95, 96, 97, 98, 99, 100,
. 0, 102, 103, 104, 105, 106, 107, 0, 109, 110,
1 111, 112, 0, 114, 115, 116, 117, 118, 119, 120,
2 121, 122, 123, 124, 125, 126, 127, 128, 129, 0,
3 131, 0, 133, 0, 135, 136, 137, 138, 0, 0,
4 141, 142, 143, 144, 145, 146, 0, 0, 0, 0,
c 5 151, 0, 0, 0, 0, 0, 0, 0, 0, 0,
5 151, 152, 153, 0, 0, 156, 157, 0, 159, 0,
6 161, 162, 0, 0, 165, 166, 167, 0, 0, 0,
7 0, 172, 173, 0, 175, 0, 177, 178, 179, 180,
8 181, 0, 183, 184, 185, 186, 0, 188, 189, 190,
9 0, 192, 193, 0, 195, 196, 0, 0, 0, 0,
. 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
. 0, 0, 0, 0, 0, 216, 217, 218, 0, 0,
. 221, 0, 223, 224, 225, 226, 227, 0, 229, 0,
. 0, 232, 233, 0, 0, 0, 0, 0, 0, 240,
. 0, 242, 243, 244, 0, 0, 0, 248, 0, 0,
. 0, 0, 0, 254, 255, 0, 0, 0, 0, 0,
. 0, 0, 0, 0, 0, 266, 267, 0, 269, 270,
. 271, 0, 273, 0, 275, 0, 277, 0, 0, 0,
. 0, 0, 0, 0, 0, 286, 287, 0, 0, 0,
. 0, 0, 0, 0, 0, 0, 0, 0, 0, 0/
________________________________________________________________
RE: Element formulations for implicit
Not all element formulations are supported by the implicit solver.
LS-DYNA will generally substitute a supported element formulation for any
unsupported element formulation requested by the user. In such a case,
a warning message will inform the user of that substitution. For example,
" *** Warning 20556 (STR+556)
Tshell formulation for part ID # 1
has been switched from 1 to 2
since the stiffness matrix is not
implemented for shell type: 1"
" *** Warning 20555 (STR+555)
Shell formulation for part ID # 1
has been switched from 1 to 2
since the stiffness matrix is not
implemented for shell type: 1"
" *** Warning 20555 (STR+555)
Shell formulation for part ID # 1
has been switched from 7 to 6
since the stiffness matrix is not
implemented for shell type: 7"
Ticket#2017122210000011
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For internal (non-public) notes on implicit materials, see text file "implicit.matls".