Did you model the bolts or use the bolt 'connector'?
Do you have any screen shots of the output?
Did you include gravity?
- gravity is included as the structure is big and not negligible, but not for bolts
- I used the bolt connector (I have read there are many issues with them but it seemed more about the surrounding of the bolt, not the bolt itself)
and applied the preload as a torque
Basically I got the stress from the bolt connector table.
I searched some more and my model and issues are very similar to this:
OK, try this - physically model a bolt in place making appropriate contact (bonded on "top" and non-pen down the sides?). Then cut a small bit out of the middle of the bolt and apply your pre-tension to the exposed surfaces facing each other, that's your bolt pre-load. Run the study and see what happens to one of these models vs. the rigid link of the 'bolt connector'.
We've had to use this 'trick' in some places.