Displacement of a helical sweep

[walkerone]

Hi,



If you create a helical sweep, is there any way to then add datum points that are constrained to the axis of the helical sweep?



i.e. imagine a spring modeled from a helical sweep - when completed,
although an axis was created in the sketch to generate the helical
sweep, there is no reference axis available in the model tree once the
helical sweep is completed.



What I actually
want to do is have points that move when the spring is then bent in
Mechanica, so that the displacement at various points along the centre
of the spring can be set as measures.



Thanks,



Walkerone

 

[Kaz Z06]

Points on the surface of your spring will force Mechanica to generate nodes at these same locations. If you create a patterned set of points on the surface of your spring spaced vertically the distance you need, you should find that Mechanica will locate nodes at these positions. This would allow you to create measures at these point/nodes that you can then calculate displacement along the axis of the spring. This will give you the vertical component of the deflection, or displacement along the axis.

I hope this helps,

Chris

 

[Ray Ellender]

Kaz Z06's idea is good for straightforward tension/compression, but it sounds like you want to bend the spring, so you could try one of the following (or all)


1. Make a series of points down the centre of the undeformed coil, one for each coil. Connect them to the coil surface using weighted links (if you have them available in your version). However you will need to make a separate surface region for each coil and use that as the attachment surface for that coil's point, so that each point is driven by the local coil displacement, not that of the whole spring - A bit of a pain, I know. Make measures on those points and Bob's your uncle! - at least I hope so, as I havent tried it


2. Make an extra part that is a solid bar that sits inside your coil spring, just touching the inner surface of the coilso that they 'bond' together when meshed. Give this a really soft material property so that it does not appreciably affect the stiffness of the spring. Run the analysis and then the deflected shape of your bar may give you what you want. You could always export that deflected shape using vrml and bring it back into Pro/E (You could try variations on this technique using different shapes if you wished, eg a dummy helix that sits inside your spring extending to that axis, with points on it, again of a soft material) (Mind you I haven't tried it to see if it works)


3. Or use Kaz Z06's idea, but with more points, say 4 per coil, so that you can capture bending (will need to make a lot of measures (another pain) and do some post-processing to get the equivalent central point)


Regards


Ray Ellender, Elite Consulting, UK

 

[chary4u007]

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