Evaluating Gasket Tightness

This multi-part tutorial shows how to create an advanced oSP3D analysis, combining multiple field-MOPs and a custom algorithm. The oSP3D analysis is then exported as an FMU, allowing consumption with Ansys optiSLang or Ansys Twin Builder, which is part of Electronics Desktop.

The objective of this analysis is to determine if the gasket is tight, given a certain bolt pretension and pressure of the flowing medium.

For background information, see Gasket Tightness in the optiSLang 3D Post-Processing User's Guide.
To learn how to create a design of experiments from an Ansys Mechanical project using optiSLang, see Exporting Field Data from Ansys Mechanical for Use in oSP3D and optiSLang.

The folder oSP3D_examples\ansys\gasket contains the files that are used in this tutorial. Because the oSP3D database file gasket_tightness.sdb already contains imported simulation data and field-MOPs, if you load this file, you can skip to Exporting the Custom Analysis Workflow as an FMU. However, if you want to step through the entire process in a new oSP3D database file, perform the procedures in the next two topics.

Identifying the Contact Tightness Algorithm

To identify the contact tightness algorithm.

Select File > Macros > Manage macros.
In the Manage macros window, select the macro identifyContactTightness and click Edit.
In the Edit chunks / macros window, the Input arguments area displays two scalar parameters that tune the algorithm (minimumPressure and minimumContactState) and two variables of type string that set the named selections of the inner and outer closed rings across which tightness is to be evaluated.
After viewing these arguments, close the Edit chunks / macros window and then the Manage macros window.

Importing Simulation Data and Creating Field-MOPs

In a new oSP3D project, import the simulation data:

To import the reference mesh, select File > Mesh > Set reference mesh and open sos_mesh.cdb in oSP3D_examples\ansys\gasket\workflow\gasket.opd\Sensitivity\Design0002\dp0\SYS-6\MECH\SoS_Export.

Note: Design0001 failed and no mesh was exported during the DOE.
To import named selections for the inner and outer edges:
1. Select File > Mesh > Import named selection from CSV and open ns_gasket_seal_edge_inner.csv in oSP3D_examples\ansys\gasket\components.
2. Set the identifier to INNER_EDGE and create a node set.
3. Select File > Mesh > Import named selection from CSV and open ns_gasket_seal_edge_outer.csv in oSP3D_examples\ansys\gasket\components.
4. Set the identifier to OUTER_EDGE and create a node set.
Caution: The identifiers for the named selections must be set precisely to INNER_EDGE and OUTER_EDGE. Otherwise, the identifyContactTightness algorithm fails.
To import field designs:
1. Select File > Process multiple designs > Import field designs.
2. In the Files to parse area, add the LS-PrePost output file sos_results.k in Design0002\dp0\SYS-6\MECH\SoS_Export.
3. Set Path of reference design to \oSP3D_examples\ansys\gasket\workflow\gasket.opd\Sensitivity\Design0002\.
4. Finish the import.
The number of field designs imported should be 45.
To import scalar input parameters:
1. Select File > Import data > Import scalars from optiSLang .bin and open StartSet.bin in oSP3D_examples\ansys\gasket\workflow\gasket.opd.
2. Accept the default values in the Import scalar parameters to oSP3D window.
3. Select Edit > Deactivate incomplete designs.
  
  Note: During the DOE, some designs have failed to produce results. Designs without field results must be excluded from field-MOP training.
To create field-MOPs:
1. Select Field data models > Field-MOP > Create Field-MOP.
2. Drag and drop all scalar quantities to the Input (selectable) list.
3. Drag and drop the field node quantities STATUS and PRESSURE to the Output list.
4. Click OK to create the field-MOPs with the default settings.
By evaluating the two newly created field-MOPs, you are now ready to approximate the contact pressure field and contact state field for any given set of input parameters (within the range of training data).

Exporting the Custom Analysis Workflow as an FMU

To determine if the gasket is tight for a given set of input parameters, you can export the macro-based custom analysis workflow as an FMU.

Note: If you skipped to this step after loading the oSP3D database file gasket_tightness.sdb, you can export the custom analysis workflow in this database file as an FMU.

To export the custom analysis workflow as an FMU:

Select File > Export for simulation > Macro-based FMU.
In the Custom solver definition window, click Add Macro.
Select Evaluate Field-MOP nodeEvaluateFieldMOP.
Click Next.
In the fieldMOP field, enter PRESSURE.
From the fmopIdent list, select PRESSURE.
Click Finish.
The macro is added to the custom solver definition.
Click Add Macro.
Select Evaluate Field-MOP nodeEvaluateFieldMOP.
In the fieldMOP field, enter STATUS.
From the fmopIdent list, select STATUS.
Click Finish.
The macro is added to the custom solver definition.
Click Add Macro.
Select Identify tightness of a contact area.

Enter the following information:

Field	Value
pressureField	PRESSURE
isTight	isTight
contactField	STATUS
minimumPressure	minimumPressure
minimumContactState	minimumContactState
Named selection	ns_gasket_seal_edge_inner
Named selection	ns_gasket_seal_edge_outer
tighnessField	tightnessField

Click Finish.
The macro is added to the custom solver definition.
Add additional macros of your choice.
For example, you might add the macro for extracting the maximum value of the PRESSURE field.
Click Next.
Click the folder icon.
Select a file name, type, and location for your exported FMU file.
Click Save.
The file path is added to the Output file field.
Click Finish.

Executing the Exported FMU

In a tool of your choice, execute the exported FMU. The following tools are recommended:

Ansys optiSLang (FMU_oSL3D custom integration node)
Ansys Twin Builder
FMPy in a Python environment