INTERACTION#
Description#
This option allows addition of various variable interactions in the
gen_evp
behavior object.
Syntax#
The syntax of the interaction types depends on the type of interaction. Generally there will be a specification of the type of interaction and two identifying tokens which define the variables which interact. This structure is summarized below:
**interaction
[ type ] item1 item2
\(~\,~\,\) …
where type may be from the following types:
CODE |
DESCRIPTION |
---|---|
|
Crystalline isotropic hardening interaction. |
default
In the absence of type the default “state” interaction will be implemented as described by [M20]. This interaction calculates associated forces including terms of other internal variables. The coupling will be stated by using the (user supplied) name of a potential and the (user supplied) name of hardening mechanisms.
**interaction
P1::
H P2::
H <COEFFICIENT>
iso
This interaction will link the isotropic variables of one class of slip systems with another (latent strain coupling) between two mono-crystal potentials. The coupling is written:
(426)#\[R_i = R_{o_i} + Q_i \sum_{j=1}^{n}(1-e^{-bv_j})h_{ij}\]syntax for this type of coupling takes the names of the two potentials, and a coefficient definition named
h
:**interaction iso
name1 name2 \(~\,~\,\)h
<COEFFICIENT>Note
for interactions between slip systems within one potential one should use the SLIP_INTERACTION class.
Example#
This is an example of the state-law default coupling to link two kinematic variables in a time-dependent viscoplastic potential and a time-independent plasticity potential.
The example material definition for this type of interaction is as follows:
***behavior gen_evp
**elasticity isotropic
young 170000.0
poisson 0.30
**potential gen_evp ev
*flow norton
n 1.0
K 20300.
*kinematic nonlinear X1
C 2000.0
D 50.0
*isotropic constant
R0 20.0
**potential gen_evp ep
*kinematic nonlinear X2
C 25000.0
D 10.0
*isotropic constant
R0 850.0
**interaction ev::X1 ep::X2 25000.0
***return
The names X1
and X2
were given in order to have readable
names for the kinematic variables. In this syntax it is important to
notice that a specification ev::X1
is different than ev::X1
because the kinematic names are localized within each potential.