Anisothermal variables management#
Anisothermal variables#
The Anisothermal variables command
represents the main contribution
of this new 8.4 version.
In the proposed methodology, the material model is first calibrated on isothermal experiments using the previous Sim-Opt commands. In this context, an optimal set of coefficients is thus obtained for each temperature.
The first aim of the Anisothermal variables command
is to provide
tools allowing to verify the evolution of those coefficients on the
whole range of temperature. Global functions, that allow to monitor the
evolution with temperature of critical material properties (eg.
\(R_{O2}\) yield stress) that may be expressed as a particular
function of the material model coefficients can be used.
The second aim of the Anisothermal variables command
is to simplify
the anisothermal models identification method. The idea consists of
creating anisothermal variables based on the current simulation
variables, and then fitting those new variables to the experiments
defined for different temperatures. For instance, if the user has
launched five optimizations to fit eight simulations to eight
experiments defined at five distinct temperatures, the user can use the
Anisothermal
variables
command
to transform the current
simulation variables into temperature dependent simulation variables.
Such an approach needs the creation of a template file including the
temperature depend-ant simulation variables that will appear in the
Variables dialog
. The user can then launch one optimization on the
temperature depend-ant simulation variables to fit at the same time the
experiments defined at five distinct temperatures. One can consider that
this optimization amounts to fit the temperature depend-ant simulation
variables to the best values of the current simulation variables stored
in the histories (typically one history per temperature value). The
Update sim command
allows finally to create, at any temperature
chosen by the user, new simulations based on the temperature depend-ant
simulation variables.
Such a proceedings may be decomposed into four steps :
fit the set of optimization
variables
for each temperature value the solution of which is stored in anhistory item
;create
anisothermal variable items
from the coefficients optimized for each temperature value :evolution of the coefficients versus temperature may be plotted ;
global functions definition from several
anisothermal variables
(for instance 0.2% yield stress) that allows to evaluate the model built from tabulated temperature values ;for each
anisothermal variable
, definition of an analytical function the coefficients of which may be optimized versus the tabulated temperature values ;
automatically add new items that contain the anisothermal behavior :
automatic creation of the template file corresponding to the chosen material file ;
automatic creation of new optimization parameters that are the coefficients of the functions attached to the
anisothermal variables
;creation of isothermal
simulation items
that use the anisothermal material file ;
execution of a whole optimization that implies the optimization parameters containing the anisothermal behavior.
Anisothermal variables management dialog#
The dialog is represented hereafter. The dialog can be decomposed into
four parts. The first frame includes the anisothermal variables
and
their definition based on experimental data, the second concerns the
parametric functions used to work out the anisothermal
variables
, the third contains the global functions, built from
several anisothermal
variables
, while the last includes the
current command buttons.
An anisothermal variable
is created in the database from its
corresponding variable
when its definition versus the parameter
values is done, its representative function is associated, and when the
Update var command
is clicked.
\(\bullet\) At the top of this dialog, the first frame contains on
the left a selection box that lists the anisothermal variables
on
which the sub-commands on the right can be activated, as described in
the next pages. Note that the selection box is by default filled with
all the variables
.
Def var command#
This command allows to define the values of the
anisothermal variable
selected versus the parameter (temperature)
values. By hitting the Def var command
, the user opens a dialog
shown in the next figure.
By default, variable
and parameter values are stored into a table
constituted by five rows, the first two being activated. Addition of new
definition lines is still possible by means of the Add row
button.
Note that an added row is activated by default (see the checkbox at the
beginning of each line). The Sort
button allows to sort the lines
according to the parameter column. If the user clicks on the Go
button despite of a not sorted parameter column, an error message is
printed. The Set column
button may be used to set a whole column to
a constant value, as shown in the next figure.
The Go
button updates the definition of the selected
anisothermal variable
with the informations included in the dialog,
while the Cancel
button closes the parametric
definition dialog
without further modification to the definition of
the selected anisothermal variable
.
Mod var command#
This command allows to modify the definition of the
anisothermal variable
selected. If the user tries to modify an
anisothermal variable
not previously defined, an error message is
printed. Note that this command opens the
parametric definition dialog
corresponding to the selected
anisothermal variable
.
Example#
The dialog shown in the next figure illustrates the definition of such
an anisothermal variable
.
Fill from hist command#
The aim of the Fill from hist command
is to define at the same time
all the variables
selected in the Variables selection box
, by
using the best values of the current simulation variables stored in the
histories (typically one history per temperature value). When the user
clicks on this command, a warning message is printed to recall that the
use of the Fill from hist dialog
will modify the parametric
variables
already defined. By hitting the Fill
from
hist
command
, the user opens a dialog shown in the next figure.
history items
list. The user is then supposed to
associate the selected history item
to a parameter value in the
right column. Note that all the variables
implied by the selected
history item
will be associated to the parameter value, while the
others (listed in the anisothermal variables selection box
but not
included in the selected history item
) will be associated to the
parameter value too, but with their own value reduced to null. The
Go
button updates the definition of all the
anisothermal variables
with the informations included in the
dialog. Addition of new definition lines is still possible by means of
the Add row
button. The Sort
button allows to sort the lines
according to the parameter column. If the user clicks on the Go
button despite of a not sorted parameter column, an error message is
printed. The Cancel
button closes the Fill from hist dialog
without further modification to the definition of the
anisothermal variables
.anisothermal variable
with temperature. At the top of the second
frame, a combo box may be used to select a function among a list
stored in the functions_data_base
file. When the user selects a
function, its expression appears in the textfield.Plot func command#
This command allows to plot the function selected in the
functions_data_base
file. Note that only the functions of the
functions_data_base
file can be plotted by hitting the
Plot func command
. If the combo box displays the no function
or
the user's function
option, an error message is printed if the user
clicks on the Plot func command
.
The dialog shown in the next figure illustrates the plot of a function
stored in the functions_data_base
file.
The textfield may be used to build user’s function not obviously based
on functions included in the functions_data_base
file.
Go command#
This command assigns to the (previously defined)
anisothermal variable
selected the function the expression of which
is written in the textfield.
More command#
This command allows to define or modify the current and min/max values
of the parameters of the parametric function assigned to the selected
anisothermal variable
. By hitting the More command
, the user
opens the More : function definition dialog
shown in the next
figure.
This dialog is based on a table that lists the parameters of the
parametric function assigned to the selected anisothermal variable
,
with their current and min/max values, and a checkbox to activate or
deactivate their optimization. The Precision
textfield corresponds
to the number of points the parametric function curve will be
constituted of. Note that the parametric function curve will besides
include all the parameter values contained in the definition of the
selected anisothermal variable
. The Go
button updates the
definition of the parametric function of the selected
anisothermal variable
with the informations included in the dialog.
The Set weights
button opens the Set points weight dialog
described in a previous section (see Optimizations/Set weights).
The Cancel
button closes the More : function definition dialog
without further modification
to the definition of the parametric function of the selected
anisothermal variables
.
Optimize command#
This command launches the Zopt module on the checked parameters to fit
the parametric function with the anisothermal variable
experimental
data. When the optimization terminates because of convergence, a window
is opened showing the best values found by the optimizer, as shown in
the next figure.
The Go
button must be clicked if the user does want to update the
checked parameters values in the definition of the parametric function
with the optimized values. Otherwise, the checked parameters values are
left unchanged.
Edit opt command#
This command opens the Zopt input file automatically generated by the
application from the informations defined in the dialog. The various
convergence parameters allowed by the optimization method selected
should be changed directly in the input file under the
***convergence section
. Default values are provided that may be
adequate in the majority of cases, so this operation is seldom needed.
The Optimization chapter of the Zmat manual describes the parameters
available to finely tune the optimization algorithm. Note that
modifications of the automatically generated input file will be taken
into account if the user hits the Save command
.
Plot cost command#
anisothermal variable
experimental data during optimization
iterations. The command can be activated to check the convergence
while the optimizer is currently running (see Optimizations/Plot cost )anisothermal variables
,
on which the sub-commands on the right can be activated, as described
in the next pages.Add command#
This command may be used to add a new global function. By hitting this
command, the user opens the
Add
/Mod a multi parametric variables function dialog
shown in
the next figure.
The Name
textfield allows to define the name of the global function.
Note that no default name is given at creation. The edition textfield is
used to write the expression of the global function. The Min
and
Max
textfields define the min/max X values of the global function
curve. Note that the Min
and Max
textfields are respectively
filled by default with the min/max values of the parameter in the
definition of the anisothermal variables
implied in the global
function. The Precision
textfield corresponds to the number of
points the global function curve will be constituted of. Note that the
global function curve will besides include all the parameter values
contained in the definition of the anisothermal variables
implied in
its definition. The Go
button updates the definition of the global
function with the informations included in the dialog, while the
Cancel
button closes the dialog without further modification to the
definition of the global function.
Example#
The next figure illustrates the definition of such a global function.
Mod command#
This command edits the global function selected. The
Add
/Mod a multi parametric
variables function dialog
is
opened allowing to change the definition of the selected global function (see Anisothermal variables/Add.
Cop command#
This command creates a new global function in the
Global function selection box
, by copying the informations contained
in the selected global function. The new global function can then be
edited by means of the Mod command
.
Del command#
Global
function selection box
.Plot command#
This command plots at the same time in the graphics area the curves
representing the anisothermal variables
(with or without defined
parametric function) selected in the
Anisothermal variable selection box
, and the ones corresponding to
the global functions selected in the Global function selection box
.
Gnuplot file command#
This command creates the gnuplot file corresponding to the curve
associated to the anisothermal variables
(with or without defined
parametric function) selected in the
Anisothermal variable selection box
, or to the global functions
selected in the Global
function selection box
. Note that an
error message is printed if the user clicks on the
Gnuplot file command
while several items are selected. The created
gnuplot file, named aniso.gnuplot
, is located in the current
directory.
Clear command#
This command clears at the same time the selections in the
Anisothermal variable
selection box
and in the
Global function selection box
.
Update var command#
This command updates the variable
database by adding as new
variables
all the coefficients of the parametric functions attached
to the anisothermal variables
defined in the
Anisothermal variables dialog
. By hitting the
Update var command
, the Variables
Creation mode dialog
(for
instance) will display the next time it will be opened the aniso-thermal
parameters in the Variables selection box
, as shown as example in
the next figure.
Update sim command#
This command may be used to create new simulation items
. By hitting
this command, the user opens the Update simulations dialog
shown in
the next figure.
This dialog contains at the top a Simulation items selection tree
that lists all the simulation items
created by means of the
Simulation dialog
. In the middle of the dialog, the temperature
textfield allows to define a temperature value for which the user wants
to create a new simulation item
copied from the one selected in the
upper Simulation
items selection tree
. The just created
simulation item
is then displayed in the
Simulation items selection tree
at the bottom of the dialog. Note
that this second Simulation items selection tree
lists only the
simulation items
created by means of this dialog, located in the
ANISO
directory itself located in the current directory. The Go
button creates the new simulation item
from the one selected in the
upper Simulation
items selection tree
, conjugated with the value
written in the temperature
textfield, and updates the database. The
Del
button deletes from the database the simulation items
selected in the second Simulation items selection tree
. The
Refresh
button updates the two Simulation items selection trees
with the informations contained in the Simulation dialog
, while the
Cancel
button closes the Update simulations dialog
without
further modification to the database.
Cancel command#
This command closes the Anisothermal variables dialog
without
further modification to the database.