Patran Session File Writer module

Note

This page relates to a legacy format, and is therefore no longer maintained.

Introduction

The Patran Session File Writer generates output in the format specified for a Patran Session file. The session file can be played in Patran to reconstruct the radiative geometrical model.

The Patran Session File Writer has been developed originally to make the thermal radiative geometry available for building the correspondence between the thermal nodes and structural finite elements. This correspondence or overlap is one of the inputs to the process of generating temperature loads for a thermo-elastic analyses. SINAS (see other pages on this site) is a tool supporting this process. The session file produced by the Patran Session File Writer constructs various items in the Patran database that can be used by the correspondence or overlap detection module that comes with the SINAS suite.

Activation of the Patran Session File Writer module

The Patran Session writer module can be selected from the TASverterGUI by setting the “Model Type” of the “To” file to “PATRAN session file”, or by using TASverter from the command line with the option:

–to_PAT=DEST_FILE.ses

Conversion from STEP-TAS to Patran Session File

Heading of the generated file

The generated Patran session file starts with comments that describe:

  • Version of the TASverter used for the conversion

  • Source file format

  • Source file name

  • Date and time of conversion

  • The unit of the length measures in the model

Furthermore the heading provides as comment a summary of the generated information and the way information is mapped from STEP-TAS to Patran entities. In addition the heading provides as comment instructions on how to invoke the generated session file in Patran.

Length unit

Patran does not provide a means of specifying the length unit to be used by the model. TASverter assumes a default length unit of metre for the length values in the generated Patran session file. This default can be overridden using the –destination_length_unit command line option to select a different unit.

If length unit conversion is applied, information about the conversion is included at the beginning of the generated model file in the form of a comment.

Meshed faces

For every face meshed on a STEP-TAS Mgm_meshed_primitive_bounded_surface (being a meshed surface and with additional information) PCL calls are generated to construct a separate surface with its normal aligned with the normal of the STEP-TAS face. This implies that for a single side active Mgm_meshed_primitive_bounded_surface that is meshed with 2 by 3 faces, 6 Patran surfaces will be constructed.

In the case of a double side active Mgm_meshed_primitive_bounded_surface, a surface will constructed for the each face on the positive side, and another for each face on the negative side. The two surfaces to be constructed corresponding to two opposite faces will be coincident, but have opposite normals. This means that for 2 by 3 mesh example above, 12 Patran surfaces will be constructed.

Thermal nodes

As indicated the Patran Session File Writer module is originally developed to provide input to the process of preparing a thermo-elastic analyses. Part of this process is building the correspondence between thermal nodes and the structural finite elements. Therefore geometry associated to each individual thermal node needs to be accessible.

For this purpose the Patran Session File Writer generates PCL calls to construct for each thermal node a separate group. The reference to each Patran surface that is generated from an active STEP-TAS face that have the same associated thermal node are collected in Patran group. The assigned group name is Sn in which n is the thermal node id.

Optical properties

No PCL function calls are generated to reproduce the optical property information stored in the STEP-TAS repository.

Meshed geometric item identifiers

The Patran Session File Writer generates PCL function calls such that the meshed geometric items in the STEP-TAS file (e.g. originating from ESARAD SHELL union or primitive SHELLs) are represented as Patran groups in the database constructed by playing the session file. All generated Patran surfaces corresponding to the faces meshed on an Mgm_meshed_primitive_bounded_surface are collected in a group with the name equal to the id of the Mgm_meshed_primitive_bounded_surface. Unions of Mgm_meshed_primitive_bounded_surface instances (i.e. Mgm_compound_meshed_geometric_item) are treated similarly by collecting all surfaces produced from joined Mgm_meshed_primitive_bounded_surface instances into a Patran group with the id of the union.

Boolean operations

There are no PCL function calls generated to perform the boolean operations. However both objects involved in the boolean operation are reconstructed and can be used for applying the boolean operation using the Patran user interface.