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ptc-49411591-Visitor
1-Visitor
October 8, 2013
Question

Optimization/Sensitivity Study Using Restricted Value Parameters

  • October 8, 2013
  • 3 replies
  • 1442 views

I'm looking to perform an optimization and sensitivy study on a tubular frame with several different sizes of tube diameters and wall thicknesses. The goal is to maximize the strength of the part for a given weight.

In order to limit the tube diameters and wall thicknesses to dimensions which can be purchased, I created a restricted parameter value list and use parameters to define the dimensions of the tubes. The tubes are being analyzed as beams so the parameter value is input into the beam section definition.

The issue is the optimization and sensitivity study immediately fail once Creo tries to analyze the part using a diamter that is not listed in my restricted value parameter. I need to limit the optimization study values to the same values that are present in the restricted parameter value list.

For example:

I have a diameter parameter that can take on values of 1.0 or 1.25. 1.0 is the default. If I choose an optimization study and input MIN=1.0 and MAX=1.25, as soon as Creo tries to calculate the next step from 1.0 (example=1.03) the study fails.

Greatly appreciate any help!


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3 replies

T
TomD.inPDX17-Peridot
17-Peridot
October 8, 2013

I am not familiar with the technique but I offer the question... can you specify the step size?

P
ptc-49411591-VisitorAuthor
1-Visitor
October 8, 2013

Antonius,

If it were possible to specify a step size in an optimization or sensitivity study (I haven't seen anywhere to specify this) it would solve half of the issue, which would be a good start.

The way tube sizes are sold in the US, the outer diameters increase in equal steps. For example, I'm trying to complete my study using 1.000", 1.125", 1.250", and 1.375" diameters which are all equal, .125" steps.

Where this will not help is determining the inner diameters. The wall thicknesses do not increase in equal steps. The wall thicknesses I'm trying to analyze for the above outside diameters are 0.028", 0.035", 0.049", 0.058", 0.065", 0.083", and 0.095". As you can see, the steps for these values are not consistent.

T
TomD.inPDX17-Peridot
17-Peridot
October 8, 2013

I very much understand your dilemma as to available materials. If it were me, I might create the original part with easy substitution in mind through relations, then analyzing each. I am more old school when it comes to this. A little effort up front can yield a highly dynamic model for analysis.

I guess I am not up to speed on the optimization and sensitivity tools available in Creo, or even if this is an optional extension. Please elaborate on how this study is performed.

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