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ptc-49323871-Visitor
1-Visitor
August 12, 2013
Question

Solid Helix with Surface Color defined by Independent Variable

  • August 12, 2013
  • 3 replies
  • 6983 views

I am trying to analyze a coil spring like structure for stress along the length of the helix. Is it possible to 3D plot a helix with thickness and a surface color along its length that is controlled by an independent variable?

3 replies

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Werner_E25-Diamond I
25-Diamond I
August 12, 2013

The thickness would be part of the data to be plotted and this has to be calculated beforehand - so it will be dependent on a variable anyway, I guess.

MC 3D Plots unfortunately does not support making display properties like color, light, viewing angle, grid numbers, ranges, ets. dependend on variables. The best you can do is using user defined colormaps.

Mabe this thread could help in that respect (while the main goal of it is something else) http://communities.ptc.com/message/195561#195561

Nevertheless it depends upon what you are after in specific if there is a workaround and solution. E.g. if you just want to higlight a specific region depending upon a variable you could create a second plot in the same graph and format that in different color. So you could create an extra plot for every part of the helox which should be in a specific color (which can depend on a parameter) and so plot the helix piece by piece. So the colors itself would be predefined in the graph, but the data to be plotted in a specific color would change depending on your calculations.

spring1.png

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RichardJ19-Tanzanite
19-Tanzanite
August 13, 2013

Nice animation. I think it's not really what Douglas is looking for, but it's nice anyway

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RichardJ19-Tanzanite
19-Tanzanite
August 13, 2013

That would require a colormap that is a function of at least two coordinates. That is not possible. This sort of graphing capability (for both 2D and 3D graphs) has been requested many times, for more than a decade. Unfortunately, other things have been deemed to be more important.

W
Werner_E25-Diamond I
25-Diamond I
August 13, 2013

As we can't map the color to the data in 3D plots I suggested to map the data to the predefined colors. It depends on what the used datastructure is, but it wouldl get rather clumsy in any way, I guess.

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Werner_E25-Diamond I
25-Diamond I
August 13, 2013

Found time to create a demo sheet to show what I was was thinking of - should get I life.

So here is a 2 coordinate colormap. The graph is prepared to use 16 colors but could be changed for more. Used two dummy functions for demonstration. Unfortunately it only works using scatter plot, so we need a rather dense grid which slows Mathcad down.

Also included another animation to demonstrate we could change color mapping over time 😉

spring2.png

M
mjolinon(byrequ1-Visitor
1-Visitor
August 15, 2013

From an engineering perspective a coil spring is simply a torsion bar which has been wound into a helix. Can you not anayse the stress for a straight bar? Give that in an ideal world the material quiality will be uniform along the lenght of the spring the stress should surely be uniform; leaving aside harmonic oscilations. Or am I completly missing the point?

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ptc-49323871-VisitorAuthor
1-Visitor
August 15, 2013

This is not really a torsion spring. It is a helix but I cannot go in any more detail in this forum. For the purposes of this discussion it is just a helix with a stress that I calculate that is a function independent of the helix but varying along the length of the wire. I would like to present it this way as a 3D helix that is colored to represent stress.

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