Files and Formats

File formats are explained in this section.

Input Files and Formats

The optimization preprocessor can only read Abaqus input files in free format corresponding to the correct syntax for Abaqus 6.1 and higher. The so-called fixed format (allowed for Abaqus 5.8) is not supported and leads to errors.

Integrating external files in an Abaqus input file by using the option *INCLUDE is permitted. This allows several input files to be used.

Important:

Note, that the *INCLUDE statement cannot be used in other Abaqus commands like for example *NODE. The use of the INPUT parameter is also permitted. The referenced filenames must not contain any blanks.

Currently, the use of parts and assemblies in the Abaqus input file is not supported by SIMULIA Tosca Structure. If the input deck is not flat, SIMULIA Tosca Structure uses an Abaqus data check run to convert the model data. This may influence the details in the input deck, especially the element and node IDs, although the structure stays the same.

When the input file is converted to the flat format using the data check run, the names of the element and node groups change: for a certain instance in an assembly, the groups dealing with its elements or nodes are named

<assembly name>_<instance name>_<group_name>.

These new names should be referenced in SIMULIA Tosca Structure parameter file if needed.

If the input file references an external file with the use of the *INCLUDE keyword, the flattened input file will contain this included file(s). That is, the flattened version will contain the data in the external files, so that only one input file is generated. If an optimization should consider several parts, it is recommended to configure Abaqus/CAE so that no parts and assemblies are written. To achieve this, the following parameter must be set in the configuration file abaqus_v6.env:

cae_no_parts_input_file=ON

Alternatively, the format may be switched during a Abaqus/CAE session:

mdb.models[modelName].setValues(noPartsInputFile=ON)

Result Files and Formats

By default SIMULIA Tosca Structure reads the results of the Abaqus FE-Analysis from the binary result file (*.fil file) and the result database (*.odb). The standard result file format is the *.odb format. If the optimization task requires additional information from the fil file which is not contained in the odb fie (e.g. stiffness matrices), the request is made automatically.

Further results, e.g. stresses at integration points, can be requested by the user without any impact on the optimization. SIMULIA Tosca Structure needs only the results at the end of each step. Therefore, we also recommend requesting other results at the end of the steps to minimize the size of the result file.

However, in SIMULIA Tosca Structure 2017 in combination with Abaqus 6.14-1 the user can change default so the results for the optimization are read from the ODB-file and SIM-file.

The novel, high-performance data format SIM can be used by the SIMULIA Tosca Structure interface to transfer stiffness matrices from the solver to the optimization system. Since this format undergoes intensive further development, the compatibility of SIMULIA Tosca Structure 2017 with respect to SIM is guaranteed only towards Abaqus 6.14-1.

Important:

  • The SIM-files from any earlier Abaqus versions than 6.14-1 are not compatible with SIMULIA Tosca Structure 2017.
  • It is recommended to use the SIM-file due to significant lower CPU-time for sizing optimization and for sensitivity-based shape and bead optimization.
  • The SIM-file is platform compatible opposite to the FIL-file, e.g. when copying from a Linux cluster to a local Windows workstation.

Changing the default from FIL-file to SIM-file is done adding the following command in the parameter file or generally, adding the command in the tosca_ctrl.cfg:

CONFIG
  $fem_modif_add_call = "$fem_modif_add_call --format_matrices sim";
  $res2vtm_add_call = "$res2vtm_add_call --format_matrices sim";
END_
Important:

If Abaqus versions older than 6.14-1 should be used, the additional command line options --format_matrices sim should be removed from the settings fem_modif_add_call and res2vtm_add_call.

Important:

  • Higher order shell elements often write wrong results in the FIL-file contrary to SIM-file having correct results for higher order shell elements.
  • In special cases the user may require all results in fil-file format, e.g. when coupling the optimization with user fatigue codes. The following command CONFIG in the SIMULIA Tosca Structure parameter file may be used to switch to the *.fil interface. The necessary result requests for the optimization are inserted automatically into the analysis input deck. 
    ${fem_modif_add_call} = "--format fil";

    ${res2vtm_add_call} = "--format fil";