Axisymmetric modelisation of shearpin

[franc11]

Hi,

I'm working with Patran 2004 and I'm tring to modelise an interference fit with a shearpin (simple full cylinder), a bushing and another part(the shear pin has different interference fit at the same time with both parts. I calculated the equivalent pressure on the shear pin made by the bushing, but I have a hard time to modelise the shear pin with Patran. How do you think I should do this. I was looking to make a 2D half model with symmetric boundary conditions. But I just don't know which kind of element to use.

Any help would be great!

Thanks!

 

[GregLocock]

What are you trying model, with your model?

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[franc11]

I want to find the stresses (mostly axial stress) due to the interference fit. Actually, the pin assemble two lugs. and there's a small gap between the two lugs. So I want to find the stresses at the beginning of the gap and see the deformation the interference fit causes to the shearpin at the level of this gap.

 

[rb1957]

perhaps a hand calc can check your model (if you know the radial compression in the pin, you know the radial strain, and hence the longitudinal expansion (due to poisson effects). I suspect that your interference is less than 0.002", and your longitudinal lengthening will be less than 0.001".

btw, whilst your problem maybe be axi-symmetric, i think you're making your life difficult modelling the pin this way, but then maybe your just trying out these features in PATRAN.

this sounds like a most unusual geometry. you're joining two members with a single pin joint (which i'd usually expect to articulate somewhat) with an interference pin (that'll fight this articulation). I'd suggest that if the joint is supposed to articulate, loose the interference; or if it isn't add another fastener to prevent any movement between the members.

 

[franc11]

ACtually, yes, there a joint that allow the two lug to articulate due to a certain force. The shearpin is there to make sure you don't apply too much force on the system. If you do, the shear pin brakes and all the system becomes useless...anyway thanks!

 

[rb1957]

i think it's very odd geometry to put an interference fit pin in an articulating joint