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I'm trying to create a block or anything else in soildworks that I can move and see the compression of the lower wire further from the arm

Something like this

exemple

The example show just one joint but I want it for a long array of joints But I have no idea how to go about it

Can you give me a direction on how to do it?

Simon
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2 Answers2

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The key point, is you need a flexible curve with a fixed length.

The simplest way to do this is with a style spline - you can add a dimension to the spline to define the length.

You can also then define the first and last construction lines to be perpendicular to the two sides of the joint, set opposing pairs of construction lines to be equal length, and set the length of the first, last, and centre points to control the minimum bend radius.

I have uploaded a .gif below showing how I set this up, I hope it's clear.

dynamic cable spline

Jonathan R Swift
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  • Perfect, thanks – Simon Mar 13 '21 at 10:07
  • BTW - is there a way to restrict the max angle? – Simon Mar 13 '21 at 22:09
  • To put a limit on the rotation of the arm inside the sketch edit environment? Not easy, but possible with more construction lines. Can’t describe in a comment though! – Jonathan R Swift Mar 14 '21 at 00:51
  • I have a problem with the solution you suggested and I don't know how to fix it - I need the line to be straight when the arm scratched it, do you have an idea on how I can do this? From 90* bend to 180 straight line – Simon Mar 14 '21 at 14:09
  • You need to draw this out for me - it's not clear what you want, and certainly not clear how that would correspond to reality. It's not a good idea for wires to be perfectly tight! – Jonathan R Swift Mar 14 '21 at 15:13
  • It's actually a Kevlar wire :) I need to specify the exact length of it so when fully starched it wont go over 180 degrees (between the two blocks) I will then make a mould in its bended state to save space Is it more clear? Apricate your help – Simon Mar 14 '21 at 16:12
  • So you are using a kevlar wire to limit the motion of the arm - fine. But how are you mounting this? I would imagine you would need some kind of anchor that is parallel to the arm, so the above method works fine, just without the perpendicular constraint? – Jonathan R Swift Mar 14 '21 at 18:02
  • yes but i have not idea how to measure the correct length of the arc – Simon Mar 14 '21 at 18:05
  • The point is, the length of the arc doesn't change? So, the length of the arc is defined by your requirement to stop the arm at 180deg? – Jonathan R Swift Mar 14 '21 at 18:13
  • Yes thats correct – Simon Mar 14 '21 at 18:14
  • Right, so what's the problem with measuring it then? It's a straight line? – Jonathan R Swift Mar 14 '21 at 18:14
  • Just didn't know how to make it straight, that's why I asked :) Trying to replicate what you did in your second post – Simon Mar 14 '21 at 18:16
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In answer to the addition question in the comments -

In the case you are describing, the cable should be anchored parallel to the beam. The length of the wire required to limit motion is self-evident from being a straight line - although you should ensure that you have compensated for stretch in the wire, and flex of its mounting under the forces involved.

Then, it's the same method to create a flexible cable that you can use to approximate a possible bent state

dynamic cable spline

Of course, you can get more complicated with it by adding additional construction lines to the style spline:

Which best represents the behaviour of your specific cable is something you will have to test experimentally, really.

dynamic cable spline

Jonathan R Swift
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