Static simulation of assembly that is in a strained state at start

[DNMakinson]

I have a set of leaf springs that are tied together at both ends via rivets. When the springs are in their free states, they don't lie on top of each other. Thus, the assy only contacts the mating points when under strain.

I presume I need to mate one end and then use a bonded interface that will pull together the needed surfaces during the simulation. I understand that this is only possible using FEM mode.

I am on Creo 4, M150

I don't have a standalone solver.

What are my options?

[SweetPeasHub]

What license for simulate do you have? Creo Simulate Lite/Standard/Advanced or Simulate Live? Or do you mean you have Creo integrated ANSYS option?

For leaf springs like this the modelling technique depends on what loading or analysis scenario you are investigating.  For example lets consider a truck bed with leaf springs. The leaf springs start out separated except at the ends. When gravity is applied and a load in the bed, the springs deform to contact more and more along their length. This could be modelled with contact conditions along the springs. However if you wanted to then check the natural frequency in the loaded state a different approach is needed. This is because modal analysis is a linear one so contacts are not allowed. In this case you need the geometry of the springs in the deflected state, close enough so you can make coincident surfaces where the contacts would be and then make a bonded connection. For example you could first do the loaded bed with contact study, then export the deflected spring shapes then reverse engineer the shape in a new CAD model and define the bonded faces. For verification you would want to check the stiffness - (slope of force deflection) for this bonded model in comparison to the one with contacts to confirm the same stiffness has been modelled. Like you suggest other FEA software can tie together parts over a gap easier. That can also cause issues however because often there is not enough scrutiny about where in the model things get joined. Even if you export to FEM and use this technique you will face the question about how far along the spring to tie them together. If you let us know about what simulation license you have and any other details on loading or screenshots you feel you can share, the community will have some better ideas for you and help you confirm whether an external solver is needed.

[DNMakinson]

This is an electrical contact arrangement. the right-most member is made of an alloy that resists stress relaxation, and it is relied upon to create the normal force at the contact face. The other two sister pieces are high conductivity copper. They will not apply any of the force, and so are formed to be in an un-stressed state when the contacts are in their "MADE" position. Thus, the pic shows all parts in free state before final assy. Thus, the stress analysis must force the (3) together in the area circled, then other constraints applied for the analysis.

I have not yet found exactly what license we have.

DNMakinson

[SweetPeasHub]

Seems doable. I have a few ideas. The time staggering can also be put on enforced displacements. (not just forces)

[DNMakinson]

I am re-opening, because, although I conceptually see what you are saying, I wonder if you can point me to a Youtube or other demonstration of this approach in action. I've never done much with assemblies. How does one "enforce a rivet"? How does one run the time dependence? Is that something I need a newer version than Creo 4?

DNM

[skunks]

I would calculate in 2D

a example att.