Simulation items management#

Simulations#

The Simulations command allows to build interactively input files for the Zsim module (see the Zmat user manual for a complete reference on this program). The simulation results can then be used to define comparisons with experimental results to drive the optimization module.

Note that simulations can be launched either from this dialog, or from the Variables Panel.

Simulations management dialog#

The main dialog is shown in the following figure. The selection tree on the right allows to select simulation items to apply appropriate commands on.

../_images/sim.svg

Add sim command#

This command may be used to create a new simulation item in the database by opening the Add/Mod simulation dialog (see add_sim).

Mod sim command#

This command edits the selected simulation item. By hitting the Mod sim command, the user opens the Add/Mod simulation dialog that allows to change the definition of the item (see add_sim).

Cop sim command#

This command creates a new simulation item, by copying the informations contained in the selected simulation item. The new item can then be edited by means of the Mod sim command.

Del sim command#

This command deletes from the database all the simulations items selected in the Simulation items selection tree.

Run command#

This command launches all the simulations selected in the Simulation items selection tree using the Zsim module.

Sel/Clear command#

This command clears all selections in the Simulation items selection tree.

Refresh command#

This command updates the Simulation items selection tree with the informations contained in the Update simulations dialog that allows by means of the Anisothermal variables dialog to create new simulation items.

Plot command#

This command draws all output curves defined in the simulation items selected in the Simulation items selection tree. Plots are tiled in the graphics area across the X-Y plane, as shown in the following figure.

../_images/simplot.svg

Set mat command#

This command may be used to set the material file of several simulations at the same time, by opening the Set material dialog shown in the next figure.

../_images/setmat.svg

By hitting the Go command, the material file selected in the Material file selection box becomes the material file assigned to all the selected simulation items. The Cancel button closes the Set material dialog.

Cancel command#

This command closes the Simulations management dialog without further modification to the database.

Add/Mod Simulation dialog#

This dialog is used to create or modify simulation items that will be run using the Zsim module. Typically the following informations are needed to define valid simulations :

  • The material behavior, defined in a material file containing values of material coefficients.

  • The simulation loading, defined by setting the evolution of components of the strain and stress tensors and external parameters (eg. temperature for anisothermal tests) against time. Mixed strain/stress loadings are allowed by Zsim.

  • The simulation output (stress/stress components, material internal variables, external parameters …) that will be stored in ASCII files.

  • Various plots that can be defined from the simulation output results to check the material response under the prescribed loading.

The dialog is shown in the next figure.

../_images/defsim.svg

The name of the simulation item can be modified in the Name textfield. The default name assigned at creation should be changed to something more meaningful to the user. The selection box at the top of the dialog is filled with the names of all template files loaded in the application, and attached to design variables as described in the Variables management chapter. Assigning a material behavior to the simulation item is done by selecting a particular file in this list.

Those template files are the basis of the mechanism that links the variables and their current values to the simulation items : when a simulation is launched, the material file selected in the Material file selection box is updated with the current values of the variables database.

The user can define the initial time of the simulation by filling the Initial time textfield command that may be used to define a non-zero tbeg starting time for the loading sequence, in which case the time values entered in the table of each load block will be incremented by the tbeg value entered. Note that the initial time is automatically filled from the first defined time of the first load block.

Concerning the load blocks, two modes of insertion are allowed, the particular type chosen being specified by means of the checkbox included in the dialog. If the Insert before mode is chosen, each created load block will be inserted before the selected load block. If the Insert after mode is chosen, each created load block will be inserted after the selected load block. Default is Insert after mode.
Various sub-commands available in this dialog are the following ones.

Add load block command#

This command opens the Define load block dialog that allows to specify manually the simulation loading (see Simulations/Define load block).

Add load block from exp command#

This command opens the Define load block from experiment dialog that allows to use an experiment item available in the database to define the simulation loading (see Simulations/Define load block from exp).

Mod load block command#

This command opens the Define load block dialog corresponding to the selected load block, that allows to manually modify the simulation loading (see Simulations/Define load block).

Copy command#

This command copies the selected load block (without suppressing it). Note that the user is then supposed to select an other load block, to choose the appropriate Insert before or Insert after mode, and to hit the Paste command.

Cut command#

This command cuts the selected load block. Note that the user can use this command to simply delete a load block, or to paste it.

Paste command#

This command pastes a previously copied or cut load block. Note that the user is supposed to have chosen the appropriate Insert before or Insert after mode, and to have selected a load block before.

Define Output command#

This command opens a window containing a selection box filled with all the output material quantities supported by the behavior selected. A material file should have been selected beforehand in the Material file selection box, otherwise the command returns an error message. The output generated in the Zsim results files is specified by selecting the required quantities as illustrated in the next figure.

../_images/simoutput.svg

The Precision textfield defines the number of digits printed for floating point values in the ASCII results files (default is 8). The Clear button clears the current selection. The Go button updates the database with the current selection, while the Cancel button closes the Define Output dialog without further modification to the database.

Add plot command#

This command adds a new plot item to the current simulation item by opening the Add/Mod plot dialog described at Simulations/Define plot .

Mod plot command#

This command edits the plot item selected in the Plot items selection box to allow some modifications. The Add/Mod plot dialog described at Simulations/Define plot is opened with the current definition of the plot item.

Del plot command#

This command deletes from the simulation item definition all the plot items selected in the Plot items selection box.

Set names command#

This command assigns to all the defined plots a name constituted by the name of the simulation item and the rank of each plot in the Plot items selection box.

Go command#

This command updates the database with the definition of the simulation item currently edited.

Edit file command#

This command edits the Zsim input file generated automatically by the application from the informations defined in the present dialog. Some Zsim commands can be directly input in this file, and will be preserved each time the file is re-written by the application. In particular, the following commands are only accessed by means of the input file (see the Simulation Chapter in the Zmat manual for a description of the syntax) :

  • **solver command

  • *integration command in the **model section

Default values are provided for these commands however, such that direct access of the input file is seldom needed.

Run command#

This command launches the simulation currently edited using the Zsim module.

Plot command#

This command draws all curves stored in the plot items attached to the current simulation. Plots are tiled in the graphics area across the X-Y plane.

Cancel command#

This command closes the dialog without further modification to the database.

Define load block dialog#

When this command is activated for the first time the dialog shown in the next figure is opened.

../_images/simload.svg

Textfields for entering numerical values that define the loading are organized in a tabular manner. In this table, the first column always defines the time, and other columns represent one particular component of the loading (eg. stress/strain components or external parameters). Rows in this table can be used to set the loading components to the value prescribed at the particular time defined in the first cell of the row. Note that the first time value is expected to be always 0.0, and that the Initial time textfield should be used to define a loading that does not start at 0.0.

The checkboxes at the head of each column allow to activate/deactivate a particular loading component. The default loading corresponds to a 2D simulation (ie. only 11, 22 33 and 12 components of the stress/strain tensors are activated). To allow a 3D simulation the 23 and 13 shear components should be activated in the corresponding checkboxes at the top of the table. Similarly, definition of an anisothermal loading requires activation the param:temperature component in the last column of the dialog. The combo boxes at the head of each column, may be used to choose between a strain (etoij components) or stress (sigij components) control for this particular component.

Checkboxes at the beginning of each line can be used to add or remove a time sequence within the loading definition (the default dialog includes ten possible time sequences, even if only the first two are activated).

Note that, once the loading has been completely defined by clicking on the Go command, the next time this dialog will be opened, only line/columns selected previously will be included in the table. Addition of new loading components or time sequences is still possible though, by means of the Add param or Add row commands.

Other textfields at the top of the dialog have the following meaning :

  • the Segments textfield defines the number of output points generated in the results files between each values of the time sequence.

  • the Nb cycles textfield may be set to a ncyc non-zero value, in which case the time sequence is expected to define a cycle that will be repeated ncyc times. Note that in this case, the time values used to define the sequence are local to the cycle.

Various sub-commands defined in this dialog are described hereafter.

Set col command#

This command sets all cells of the column specified to a given value, as illustrated in the following figure.

../_images/setcol.svg

Add param command#

This command adds a new column in the loading table. The column is labeled param by default, and the definition should be changed to something like param:name where name is the name given to the external parameter in the simulation.

Add row command#

This command adds a new row in the loading table.

Go command#

This command updates the loading definition for the current simulation item, using the values entered in the dialog.

Cancel command#

This command closes the dialog without updating the loading definition.

Define load block from experiment dialog#

This command is used to define a simulation loading from an experiment item created beforehand by means of the Experiments command (see Experiments). The dialog is shown in the next figure.

../_images/simfromexp.svg

The first column in this dialog is used to define the loading components (eg. stress/strain components or external parameters). The combo boxes can be used to choose between strain (etoij components) or stress (sigij components) control for this particular component. The checkboxes at the beginning of each row allow to activate/deactivate a particular loading component. The default loading corresponds to a 2D simulation (ie. only 11, 22 33 and 12 components of the stress/strain tensors are activated). To allow a 3D simulation the 23 and 13 shear components should be activated in the corresponding checkboxes at the beginning of table rows. Similarly, definition of an anisothermal loading requires activation the param:temperature component in the last row of the dialog.

The second column specifies the name of the experiment item that will define the evolution of the loading component during time. A combo box is filled with all experiments items defined beforehand by means of the Experiments command, and the item required must be selected from this list. Note that only one experiment item can be chosen in this list for the various loading components, but the same experiment may be assigned to several loading components.

The X value stored in the experiment item will be used to define the time sequence.

If a base or derived item type is selected (let us recall that those are used to store X-Y curves) the Y value stored in the item will define the actual loading component values.

Input in the third column is only needed if a composite type of experiment item is assigned to the loading components (this type of item can store multi-column data). In this case the column number in the composite item should be given in the last column of the dialog for each loading component attached to the experiment : syntax is $nc where nc is the rank of the Y value in the composite item definition.

Example#

In the previous figure the eto11 loading component is assigned by means of the experiment item named lcf1x3_load, ie. the time sequence and the eto11 values are defined respectively by the X and Y values stored in this experiment item. Other loading components (sig22, sig33 …) are assigned to a null constant value over the whole time sequence.

Example#

The next figure illustrates the use of a composite experiment item to define a multiaxial loading. Both the eto11 and eto12 loading components are defined by means of a composite experiment item named biaxial. Within this item, the X values will define the time sequence, while the Y3 and Y2 values (the third and second Y values stored in the item, specified as $3 and $2 in the last column of the dialog) will be used to define the eto11 and eto12 components respectively.

../_images/deffromexp2.svg
The Segments textfield defines the number of output points generated in the results files between each values of the time sequence stored in the X column of the experiment item.
The following sub-commands can be activated from this dialog.

Go command#

This command updates the loading definition for the current simulation item, using the values entered in the dialog.

Cancel command#

This command closes the dialog without updating the loading definition.

Define plot dialog#

This dialog, used to create or modify a plot item attached to the current simulation item, is shown in the figure hereafter.

../_images/simdefplot2.svg

The following sub-items are accessed from this dialog.

  • The name of the plot item defined in the Name textfield.

  • The number nc of curves entered in the History textfield, corresponding to the nc more recent simulations, that will be drawn on the same plot. This type of plots is a convenient way to visualize for instance the influence of material coefficients on the simulated response.

    Example

    In this example, three simulations have been performed for increasing values of the initial yield stress R0. Plots of sig11 vs eto11 and the cumulated plastic strain evcum vs time obtained by setting the History parameter to 3 are shown in the next figure.

../_images/plothistory.svg
  • A combo box filled with the experiment items defined beforehand by means of the Experiments command (see Experiments), where a particular item can be selected to be used as a reference curve drawn on the same plot as the simulation curve.

  • Two selection boxes filled with the simulation output components defined by the Define Output command described at Simulations/Define Output. A particular component should be selected to specify the X (left box) and Y (right box) parameters that will be drawn on the plot.

The following sub-commands can be activated from this dialog.

Go command#

This command updates the plot definition using the values entered in the dialog.

Cancel command#

This command closes the dialog without updating the plot definition.