Hello,
Is it possible to incorporate a spring that acts only in tension and gives no response in compression in COSMOSMotion 2008?
Thanks,
Nathan
Is it possible to incorporate a spring that acts only in tension and gives no response in compression in COSMOSMotion 2008?
Thanks,
Nathan
Technically, it is possible, but I have not tried it in 2008.
The workflow is you first define a plot to measure displacement that governs the spring force. This is the key difference to 2007 where you could immediately use markers under any motion object to define the measurement on the fly).
Once that is defined you can write an action/reaction force function that only applies a force when the spring is in tension.
You need to know the value for the displacement plot when the spring goes into tension. this may be easy to know or require a couple of quick calcs. You write the function expression in the following form
-IF(({Displacement_plot}-750): 0,0,1200*({Displacement_plot}-750))
where 750 is the free length
1200 is the spring stiffness.
The logic here states that if the displacement is <=750, then no force is applied. If it exceeds 750, then a force linearly proportional to the extension is generated.
I beleive a negative sign is needed to get a contraction force (resist the extension), but I'm a little rusty on my motion sign conventions.
Cheers,
Ian