Need help with CBUSH Stiffness values

[ttaannggeenntt]

Hi All,

I am a fairly new to fea and have a question regarding CBUSH elements.

I am trying to model CBUSH elements to represent an M3 fastener which bolts 2 mounting holes of an angeled bracket to a surface.

What stiffness value do I use and in what in What DOF?

DO I use K = AE/L for stiffness calculations?
where A = pi*d^2/4 (where I took D to be 2.9 mm for M3)
I got A=6.6e-6
E = 1.8e8 Pa
L = .008m
I get K = 147689.4
my DOF would be fixed in 12345 and not in z since the fastener can rotate around that axis?
^^^ not sure if this is correct...

Thank you

 

[dcattoni]

Hi ttaannggeenntt

For bolt I use a High stiffness in the three traslattion direction (Like 1E6) and a low value in the three rotation direcction (like 10000).

Remember to joint cbush with coincident nodes if you want to quantify force in bolts.

bye

 

[rb1957]

be careful with CBUSH ... understanding tension/compression loads is not obvious (ie +ve loads are not necessarily tension).

another day in paradise, or is paradise one day closer ?