How Can I build a model to calculate stiffness of a tapered coil ?

[duman_mert]

Hello ;

I have been trying to construct a model that I can use to calculate the stiffness of a tapered coil. I tried constraining one end and applying remote force command but the displacement occured in more than one axes. What I need is apllying different forces and recording the corresponding linear displacement values, then I will use this displacement to calculate the stiffness. I created my coil correcrtly but could not make it compress and elongate on axis that runs through the center of the coil. Could you help me with this, what should I try ?

[image added by CM from duplicate post]

[swalton]

Please post the model.  It will help the forum experts understand the issue.

One thing to remember is that the basic FEA in Inventor does not understand large displacements.  You may need to use Inventor Nastran, Fusion 360, or a 3rd party FEA solver to get the most accurate results.

[duman_mert]

 This is the tapered coil I need to test. I can not make compressions or tensions on this specimen. How can I find the linear displacement of this tapered coil under certain forces ?

[kacper.suchomski]

This is non-linear analysis.

[duman_mert]

By linear what I tried to say was that I need the displacement along the axis through the center of the coil. When I try applying force on the spring with one end constrained it does not only comprress but also translates. I want to eliminate that translation and the spring to compress only. How can I achieve this ?

[swalton]

What limits the translation of the coil in the real world?  Use that object/design to inform the boundary constraints used in the FEA.

Another choice: Apply a forced axial displacement to the spring, and review the resultant force.  It would be interesting to see the magnitude of the translation forces.  If they are a few percent of the axial force, you may be able to ignore them.