Mechanica Fasteners with Spacers

[tdekon]

I am new to Pro/E and Mechanica and am having difficulty with the use of fasteners (screws)with spacers or sleeves between the fastened parts. I can run the sim with just 2 parts and simple fasteners, but encounter an error when I try to add spacers between the two parts.


** Error: Check model for under-constrained regions and/or insufficient
number of contact interfaces.


I first ran it with just two components without the load with no problems. Then I added spacers and ran it with the load, constraint, and fasteners and encountered an underconstrained error. I then added a free interface between part 1 and the spacers and between part 2 and the spacers, resulting in the error above.


Any help or advice would be greatly appreciated.


Thanks in advance, Terry

 

[britineeng]

We had a similar problem a few years back using ansys. a work around was to make the fastener and spacer one part. it also failed when we had clearance hole spaces too. we just closed up those spaces.


-Lou

 

[empgoalie]

I'm not sure about post WF2, but with WF2, fasteners have these requirements:

 

[paul_mcad]

Hello,

I'm afraid that nothing has changed in wildfire 4.0 either
and the rules that empgoalie stated still apply, not sure
if this has changed in wildfire 5.0

 

[tdekon]

Looking at the Valid Fastener Assembly above in empgoalie's post, I don't see why my model would not work. The sleeves/spacers are larger in ID than the fastener and would not interfere with the bolt. The valid assembly shows spacers, but they are on a different axis.


Any thoughts?





Thanks,


Terry

 

[empgoalie]

I would take the approach Britineeng suggested: Make your spacers and the top plate one part. Next, remove the welds you have in place between the bottom of the spacers (now part of the top plate) and the bottom block. Then offset the two parts from one another.