Nuts, bolts & screws in Assemblies

[tonireneirene]

I have low RAM to mesh full assembly for vibration analysis. Nuts, bolts and screws alone will cut my model size drastically.

Is there a way to approximate nuts, bolts and screw effects in an assembly so I can remove them in the solid model assembly?

 

[maxPE]

Typically in FEA the dynamic model is very coarse. All that you need to simulate is the mass and stiffness of the system. If you think that the bolts and holes affect the dynamics significantly use engineering judgement to either fill them or not. assemblies have difficulty as usually the bolts take the tension and the surfaces take the compression. I would use my judgement as to bonding the tow parts with springs or "welding' them. After all dynamics is a wave of the hand as to accuracey to the 'real world'.

Max

 

[tonireneirene]

Max:
Thanks.

Apreciate it.

Charles

 

[maxPE]

Charles, To be a little more clear, imagine a correctly preloaded bolted joint. The faces are in compression and the fasteners are in tension...springs. What do you think the nat freq of that joint is? Can be calculated by hand but its likely higher that any system resonances of interest unless you have a "very interesting" problem.

Max

 

[tonireneirene]

Max:
I see what you are saying.

Thanks for sharing it with me.

Charles