How to modify default analysis

This how-to guide explains the process to modify default analysis object in DIANA by making use of viia_modify_analysis() function in the mainscript.

This modification function is available for A10, A12, A13 and A15 analysis only. The modification that can be done using this function is also limited but it covers majority of the commonly encountered use case.

Modifying A10 or A13 analysis

Normally, an nonlinear static analysis is created as follows:

project.viia_create_datfile()
project.viia_analysis(analysis_nr='A10', run=False)

To make use of the modification functionality, the analysis has to be created slightly different, in two steps (same can be applied for A13):

Step 1 - Create analysis but suppress creation of files

Use the following command to create the analysis, notice that by setting ‘suppress_analysis’ argument to True, we are actually suppressing creation of files in analysis sub-folder.

analysis = project.viia_analysis(analysis_nr='A10', run=False, suppress_analysis=True)

Step 2 - Modifying analysis and creating files in analysis sub-folder

Use the returned analysis object to modify analysis in DIANA. We set the ‘analysis’ keyword argument to the object we created at the end of step 1.

project.viia_modify_analysis(analysis=analysis, mod_param=[[...]])

The argument ‘mod_param’ (see the expression above) should contain the items for modification. More explanation is given below for how to create input for argument ‘mod_param’. Please note that analysis files will be created by deafult in this step.

In A10 analysis, by default the step size inside the last execute block is set to 0.5 0.5 i.e. 2 steps of 0.5 each. A start step size of 0.5 0.5 is expressed as a list, [0.5, 2]. Let’s say the goal is to give input in ‘mod_param’ that modifies this to 0.1(10) i.e. 10 steps of size 0.1 each. The following command will set start step to 0.1(10):

project.viia_modify_analysis(analysis=analysis,
    mod_param=[['Structural nonlinear 3', 'Execute block D', 'Start steps', [0.1, 10]]])

When run in DIANA, this will set the start steps to 0.1(10) as visible in the image below.

Figure 56 Input for ‘mod_param’ values that are needed to change start steps in ‘Execute block D’.

It is also possible to modify multiple items in one statement. By providing multiple inputs inside the main list in argument ‘mod_param’ you can modify multiple settings.

The following example modifies the maximum number of iterations in ‘Execute Block E’ of ‘Structural nonlinear 3’ to 100. And the second, third and fourth input will remove ‘OUTPUT_1A_MAX’, ‘OUTPUT_5A’, ‘OUTPUT_GEO1’ from output items. The last one will change start steps to 0.1(10) instead of 0.5(2).

project.viia_modify_analysis(analysis=analysis_mod, mod_param=[
    ['Structural nonlinear 3', 'Execute block E', 'Equillibrium iteration', 'Maximum number of iterations', 100],
    ['OUTPUT', 'OUTPUT_1A_MAX'],
    ['OUTPUT', 'OUTPUT_5A'],
    ['OUTPUT', 'OUTPUT_GEO1'],
    ['Structural nonlinear 3', 'Execute block D', 'start steps', [0.1, 10]]])

Modifying A12 or A15 analysis

Normally an A12 analysis is created as follows:

project.viia_create_loads('Base motion')
project.viia_add_basemotion_signals(signal_list=[1, 2, 3, 4, 5, 6, 8])
project.viia_create_load_combination_base_motion('S1')
project.viia_analysis(analysis_nr='A12', run=False, signals=['S1'])

To make use of the modification functionality, the analysis has to be created slightly different, in two steps (same can be applied for A15):

Step 1 - Create analysis- A12 but suppress creation of files

Use the following command to create A12 analysis, notice that by setting ‘suppress_analysis’ argument to True, we are actually suppressing creation of files in analysis sub-folder.

project.viia_create_loads('Base motion')
project.viia_add_basemotion_signals(signal_list=[1, 2, 3, 4, 5, 6, 8])
project.viia_create_load_combination_base_motion('S1')
analysis = project.viia_analysis(analysis_nr='A12', run=False, signals=['S1'], suppress_analysis=True)

Step 2 - Modifying A12 analysis and creating files in analysis sub-folder

Use the returned analysis object to modify analysis in DIANA. We set the ‘analysis’ keyword argument to the object we created at the end of step 1 (analysis_mod).

project.viia_modify_analysis(analysis=analysis_mod, mod_param=[[...]])

The argument ‘mod_param’ (see the expression above) should contain the items for modification. More explanation is given below for how to create input for argument ‘mod_param’. Please note that in this step, analysis files will be created by default.

In the example below, we will create A12 analysis and modify multiple items in a single step. The mod_param output that is shown below does the following. Here we change maximum number of iterations in ‘Execute Block E’ of ‘Structural nonlinear 3’ to 100.

project.viia_modify_analysis(
    analysis=analysis, mod_param=[
        ['Structural nonlinear 3', 'Execute block E', 'Equillibrium iteration', 'Maximum number of iterations', 100]])

Examples

This section will give some examples of how to define the argument ‘mod_param’ properly when using viia_modify_analysis().

Example 1 - Deleting unnecessary output items

Let’s say we want to delete some output items from either A10 or A12 analysis.

Figure 57 Output items selected for deletion.

project.viia_modify_analysis(
    analysis=analysis, mod_param=[
        ['OUTPUT', 'OUTPUT_GEO2'],
        ['OUTPUT', 'OUTPUT_GEO3'],
        ['OUTPUT', 'OUTPUT_GEO_REF'],
        ['OUTPUT', 'OUTPUT_MOVIE']])

Figure 58 A12 analysis after selected output items has been deleted.

Please note that the same input for argument ‘mod_param’ can also be applied to A10 analysis to delete few of the output items.

Figure 59 A10 analysis after selected output items has been deleted.

Example 2 - User input for node number in an output block

Let’s say we want to change the node numbers in some output blocks from either A10 or A12 analysis.

Figure 60 Node numbers for output block 3 in A12 analysis - before user input.

project.viia_modify_analysis(
    analysis=analysis, mod_param=[
        ['Structural nonlinear 7', 'OUTPUT_3', 'user selection','nodes', [50,168,880,2253]]])

Figure 61 Node number for output block 3 in A12 analysis - after user input.

Similar to the previous example, the modification of analysis can be applied to A10 as well, example of which is shown below.

Figure 62 Steps in the output block OUTPUT_STATIC-NL in A10 analysis - before user input.

project.viia_modify_analysis(
    analysis=analysis, mod_param=[
        ['Structural nonlinear 6', 'OUTPUT_STATIC-NL', 'steps',[2]]])

Figure 63 Steps in the output block OUTPUT_STATIC-NL in A10 analysis - after user input.