sheet metal and rivets?

SteveMelton

what is the best method in Mecway to simulate rivets in sheet metal structures (shell elements) at this time? .... similar to CBUSH spring/damper. this analysis is primarily for frequency response, not stress.

disla

..

SteveMelton

hey, the 1d beam bolded connection is neat. however, I have LOTS of rivets and was looking for a way to model them easily such as CBUSH (spring/damper) at rivet nodes, no holes. for this rudder, since I am only looking for frequency response, I may simply bond the riveted surfaces.

disla

That's the link sorry : https://mecway.com/forum/discussion/1150/1d-beam-bolted-connection

I may simply bond the riveted surfaces.

That's why I erased the post. Contact with separation do not work in Frequency analysis so you need to bond both surfaces and then 1D bolts are really non sense.
Just made a quick test and there is penetration.

Maybe if you go to *STEADY STATE DYNAMICS HARMONIC=YES (default) you could recover it.
I know there's people in the forum Who have already been able to set it up with custom cards.

SteveMelton

yes, a bonded connect may be OK for frequency analysis. not looking for any stresses.

Mishal

If you keep the contact and run a nonlinear dynamic the results can be processed to get the natural frequencies. You would need to do this out of Mecway

SteveMelton

after running some test frequency response models using various connectors for rivets: beam, spring, bonded faces... I found unacceptable variation in the response for the methods. I decided to find a way to use RBE3-CBUSH-RBE3. working the model in hypermesh.

disla

Hi and Happy New year everybody,

How is the animated solution constructed when performing frequency or buckling analysis?
Unlike static, this type of analysis does not seem to interpolate between the model at rest and the solution.

I ask this because the solution for Frequency with or without contact is different. I was hoping that the contact card wasn’t really going to have any effect, but it seems to change the solution.

If the animation for this kind of analysis is built interpolating against the symmetric solution for displacements there is no way a no penetration contact, only compression or only tension problem can be properly represented/animated ¿isn’t it?.

Victor

@disla, yea, it just varies the deformation scale factor symmetrically between + and - some value to animate it. Mecway chooses what it thinks is a reasonable amplitude based on the displacements and geometry so it might be different sometimes.