bolt connection restraints
bolt connection restraints
(OP)
I'd like to analyse a 3d static structure with Designstar. The structure is hinged with 2 plates with a hole of 11mm. Through the holes are 10mm axles with a simple nylon bushing. I'm trying to find out what will fail under load, the beam or the hinges.
----- | F
-o---++++++++++++++++++++++++++++
-----
>-----
- = plate
o = hinge
+ = beam
| = force
> = prescribed restraint, no translation in x-direction
I'd like to analyse this by putting a restraint on the holes, but i don't know which restraint i have to use. The structure can rotate around the bolts, but i don't know how to apply a restraint for that kind of condition. Maybe it is better to model the complete bolt and specify some kind of contact condition?
Thanks in advance,
Ikkedus
----- | F
-o---++++++++++++++++++++++++++++
-----
>-----
- = plate
o = hinge
+ = beam
| = force
> = prescribed restraint, no translation in x-direction
I'd like to analyse this by putting a restraint on the holes, but i don't know which restraint i have to use. The structure can rotate around the bolts, but i don't know how to apply a restraint for that kind of condition. Maybe it is better to model the complete bolt and specify some kind of contact condition?
Thanks in advance,
Ikkedus





RE: bolt connection restraints
I'm assuming you know your structure must be stable in order to perform a typical statics analysis. Otherwise the structure stiffness matrix will be singular, causing the software to fail to find a solution.
RE: bolt connection restraints
This approach gives you a conservative analysis of your axle because it neglects bending resistance of the nylon bushing, which might be relatively low, anyway, depending on the scenario. Not necessarily a bad approach.
But if you have a bolt (or axle or hinge) that terminates at a plate, indeed release the torsional dof at one end of the beam element, as described in my first post.
RE: bolt connection restraints
David R. Dearth, P.E.
Applied Analysis & Technology
RE: bolt connection restraints
thanks for your answers.
this week i found a way to model the bolt and apply a surface contact condition that works quite well. The result matched the value of deformation that was found in a 'real life' test very well. At the moment i'm analyzing the other models with the same kind of hinge but different loading and plate thicknesses.