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Global sensitivity output


Global sensitivity output

Hello All,

Is there a config option (hidden or otherwise) to persuade Creo to output FULL results at each step of a Global Sensitivity study?

I know GS studies aren't meant for this but you don't know until you ask.

The reason for the requirement is as follows:

  • A stand alone analysis 'ANALYSIS1' performs a calculation of a single geometry configuration and is 90% the use of the software.
    • OUTPUT = Full stress, measures etc
  • A global sensitivity study is used to adjust a dimension(s) over a desired range
    • OUTPUT = Measures at each step along the dimension range NO full stress plots
    • limitations of use include multiple loadstep Analyses - warned and reduced to single step.
    • Remeshing may take place if element editing limits are violated as a result of an underlying geometry change
  • One or more stand alone studies can be called can be called by a STANDARD design study.
    • OUTPUT = Each study has its own Full results directory beneath the Standard study directory
      • OPTIONALLY - The user can input one or more 'offset dimensions' that will cause the original model to regenerate to a new configuration before running the one or more stand alone studies. The SAME dimension are used for each study.
    • OUTPUT = Each study has its own Full results directory beneath the Standard study directory. The SAME 'offset' geometry configuration for each study
    • Remeshing - The standalone studies use identical geometry and so there is none and this is a desirable quality.

So what seem to be missing is the ability to move something eg. a sleeve sliding along a pin. at get full results at a number of positions WITHOUT having to invoke a lengthy and often troublesome large displacement study.

Each position of the example sleeve on the pin as a stand alone study would be a straightforward contact study (well, as straight forward as contact studies are) but without the requirement of a large displacement.

This is a 'rigid body motion' static analysis requirement not an LDA requirement.

Yes. I know. Why don't I just run N models, each one at a new position ... well, this is because

  • Mechanica will NOT reuse a mesh if there is a large movement of a component. It will fail and remesh even if the only change the component has undergone is its global position wrt WCS.  The original elements in the mesh file know where they are in space (co-ordinates) and the geometry has now moved.
  • Remeshing means the meshes are not consistent from one model to another. Different topology.
  • Even identical analyses run back to back will have the same node numbered differently. I've asked about this before and I think the answer was : Mechanica was built that way.

Yes. I know. Why does it matter?

Fatigue software calculations use nodal information. As with most real engineering loads are not 0,1 or -1,1. Things move as mechnisms and a point in a structure sees a different forces at different times. So we need to gather the stress-time history for each consistent node position and this falls flat on its face if the software renumbers everything even if it hasn't remeshed.

Modern Fatigue stuff is on the radar now and I am looking for a work around that doesn't use the LDA route as I don't have a big enough disk and my estimate for a run time is 18 weeks.

Thanks for getting this far.



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