Troubleshooting

When Tosca Structure.smooth is started from Tosca ANSA® environment or Tosca Structure.gui, the warnings and error messages are written in the file TOSCA.OUT in the subdirectory TOSCA_POST of the job directory. In Tosca Structure.gui, this information is also displayed in the lower part of "Start SIMULIA Tosca Structure" screen (if Tosca Structure.pre screen is used for defining Tosca Structure.smooth parameters) or, otherwise, in Tosca Structure.smooth screen. These warnings and error messages describe the problems that occurred during the run of Tosca Structure.smooth, such as wrong parameter file syntax, missing input files or problems with creating output files. The parameter file for Tosca Structure.smooth created by Tosca ANSA® environment or Tosca Structure.gui is located in the job directory and has the name <jobname>_smooth.par; the information in TOSCA.OUT file refers to the values from this parameter file.

Besides the syntax mistakes, misspelled file names and invalid values of parameters, following problems may also lead to erroneous behavior of Tosca Structure.smooth:

  • Unfeasible target relative volume.

    If this value lies outside of the range of relative volumes attained at isovalues equal to 0 and 1, an error message is produced since it is unlikely that such relative volume will be attained at any isovalue. The error message suggests what values may be used as the target relative volume.

  • Models with "jumps" of relative volume.

    In some cases, the relative volume depends non-continuously upon the isovalue, and therefore it may happen that a certain target relative volume cannot be obtained. Typically, it happens when the target volume is larger than the total volume of all non-empty elements of the model, or otherwise in small models. The iterations do not converge and stop when the maximal number of iterations (currently 20) is reached: 

    Preparations for iso-cut finished
-- Iteration 1: iso_value = 0.000, rel. volume = 1.000
-- Iteration 2: iso_value = 1.000, rel. volume = 0.040
-- Iteration 3: iso_value = 0.625, rel. volume = 0.105
-- Iteration 4: iso_value = 0.419, rel. volume = 0.218
-- Iteration 5: iso_value = 0.261, rel. volume = 0.260
-- Iteration 6: iso_value = 0.135, rel. volume = 0.326
...
-- Iteration 19: iso_value = 0.001, rel. volume = 1.000
-- Iteration 20: iso_value = 0.001, rel. volume = 0.355
**** TOSCA Structure Smooth ERROR ****
Target volume not attained; the isosurface is not saved

    In the example, the target volume is 0.4. Here, one can only attain relative volumes either between 0.04 and 0.355 or equal to 1.0 (this happens if the isovalue is below 0.001: the surface of the whole model is produced since all elements have material values above 0.001). Here, the solution might be to set the target volume to 0.355 or lower, or set a fixed isovalue (e.g. to 0.135 in order to get relative volume equal to 0.326).

  • Inconsistent meshes.

    Tosca Structure.smooth assumes that the mesh is conforming or can be made conforming by simple operations, like subdividing a quadrangle into two triangles. In this case, a mesh is considered to be conforming if any two elements that have an area contact have exactly one entire common face. Some meshes contain degenerated elements or irregularly subdivided elements and in result violate this rule, and then Tosca Structure.smooth is not able to complete the isocut. An error message typically looks like this:

    **** TOSCA Structure Smooth ERROR ****
Error in SurfaceGenerator::RemeshPolygonsFromEdgeList: a
node has more than 2 adjacent nodes
Report this problem and the circumstances under which it
arose to your customer support representative, making any
PARAMETER FILE and FE SOLVER INPUT FILE available as part of
the report.

  • Self-intersecting surfaces.

    Although Tosca Structure.smooth is able to prevent new self-intersections, those that are present in the original model are likely to remain. Coplanar faces with common inner points also count as intersecting; thus, a warning of large number of self-intersections happens e.g. if a wall inside of a solid structure exists and is remeshed differently from both sides. This wall will also remain inside of the resulting surface. In Tosca ANSA® environment, the self-intersections of a surface might remain after RECONSTRUCT (in rare cases, RECONSTRUCT creates new self-intersections that in turn makes SOLID_MESH fail.

  • Meshes with inner holes.

    If the model contains an empty domain that is completely surrounded by material, the calculated volume will be incorrect as the volume of this hole will be added to the total volume instead of being subtracted. Otherwise, this has no effect on Tosca Structure.smooth. It might be suspected that the inner holes exist if a message "Surface is disconnected; the number of connected components is ..." is produced and the number of connected components is too large. The parameters RESULT_FILTERING and COMPONENT_LIMITING_SIZE are designed to solve this problem.

If an error occurs during the generation of an output file, a warning instead of an error is produced so that the remaining output files could be generated. Such warnings might help understand why the files cannot be saved.