Shake and Vibration, whole chassis?

[drvogler]

Guys,


I haven't messed with Mechanica/simulation very much at all. Did some simple load analysis about 5 years ago (way before Creo)...


I have some direction to try modeling shake and vibration profiles on our whole product. This is typically about 50 parts, maybe 500 fasteners though...


What kind of luck has anybody had doing complex assemblies?


Also, how do you guys deal with things like cabling? We only design about 10% of our cables in Creo/ProE... But there's significant weight in cables (especially if they have ferrite beads).


Where do you guys get standard (Mil Spec?) shipping and shake profiles?


Any help appreciated.


Dave

 

[mneal]

I haven't used Mechanica for FEM in quite a while but I believe it has/had a fastener element that is basically
creates a beam between holes.If you only want a ROM
then I would think about eliminating the hardware and
merge the mated surfaces. (only do if you don't care
about interface stresses and stresses present within the
hardware obviously)

I typically add dummy mass to represent connectors on the various assemblies. If you have significant mass in the
cables themselves I think you would have to add discrete
mass at the tie down points.I wouldn't try to model
the cables unless they are very stuff and you have a very
good reason too. (Mechanica cant do any large
deflections/nonlinear stuff because of the P type solver
it uses)
MIL-STD 810 has some good typical vibration input curves
for various transportation methods.