I am trying to simulate and analyze a stresses in a tower that is supported by four guy cables.
How can I simulates/analyze these cables in pro mechanica?
thanks a lot
If you want to idealize them, I think you could use beams.
As SA said, idealization with one directional element.
But how to add one directional idealization element ?
Patrick,
After seeing some of the replies, I figured I would take a stab at this one. If I understand your post correctly, I think what you are looking to do is to simulate the forces these guy cables will apply to your structure based on some change in end-to-end deflection of those cables. The posts on using a one directional element are correct and this is what I did to setup a one directional element.
- Create simple point to point springs for your guy cables, but set these springs up using a force/deflection curve.
- When setting up the force/deflection curve you can use symbolic equations or a table, I went with a simple symbolic equation using an IF/THEN statement.This equation shows that when the spring deflection is less than zero, the force is equal to zero (compression). When the deflection is at or greater than zero, the force is a simple linear function (tension). The tension side of my equation is basically Hooke's Law, F=kx.
- These guy cables are most always pre-tensioned, so you would want to adjust the equations I have slightly to account for this. Also remember that the tension side of the equation does not have to be linear either, I just showed it that way for simplicity
- I put in a force measure on each spring, just as a way to show what is happening in those springs for different scenarios.
- My structure is a simple cylinder, and it does have points on it for attaching the springs. the other end of the springs goes to ground and those ends can be constrained
- With the way I have this setup you need to run a nonlinear analysis in Mechanica.
- When running the analysis Mechanica will alert you that you have springs that may have very low stiffness, which is OK if they are not being put into tension.
- I tested this out in numerous ways to see if the springs would react as expected and everything seemed to work well.
Hope this helps,
Jon
Thanks Jon, It really helped, but I was unable to setup equation as my spring defenition form look different. Have a look.
My Creo Version
Thanks Again
Shinto Mathew
Shinto,
I am pretty sure that this newer spring functionality was implemented in Creo 1 release.
Thanks,
Jon
Simplifications with non-linear spring works for some extent, but if you need to get pretension or forces due rope weight (http://en.wikipedia.org/wiki/Catenary) youll run out of luck. Beam elements are not the answer either.