Plate and 'Floating' Pin Connection

[MrK159]

Hello, I am new to the forums but have a few years running NX. This is a great place with a wealth of information.

My question is, what would be the optimal connection for two horizontal plates (one with a though hole for the pin/threaded portion and the other on top resting on the pin). The plate is sitting on top of four of these adjustable pins for plate height adjustment while four inner bolts keep it locked in place. The load is applied on the top plate. I have the inner bolts connected using the typical spider/CBEAM connection, but was wondering how you would go about making the contact for a flat plat resting on a rod/pin. Would a spider on the bottom plate with a Point to Face connection connecting the other plate? Could I just divide the face with the diameter of the pin and then spider the divided circular section? The pin would need to be Free to move in any DOF except vertical obviously.

Thanks!

 

[rb1957]

is the pin free to move once everything is tightened down ?

i find your description somewhat difficult to follow ... a sketch maybe ? it sounds like you have one plate mounted onto another which is attached to surrounding structure ("the rest of the world"), and there's some leveling feature on the inner plate (maybe a threaded shank with two jam nuts (one on either side of the larger plate) ?

which is all very nice but is the point of the question how to model the loadpath between the bolt and the surrounding plate (particularly since there's a clearance) ?

personally, i'm often "lazy" in this detail since it usually isn't critical for my design. i model the bolt center and spider that to the bore of the hole.

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

 

[MrK159]

Yes you are exactly correct in description of how everything is interacting. Since I am using a midsurfaced plate with 2D elements, would the spider have any influence on the mesh (acting like the rod is going though to the center of the plate). I tried this with one of the connections as a test and it seemed to reflect what I am trying to achieve. I also removed all DOF with exception of the vertical translation.

 

[rb1957]

"removed all DOF with exception of the vertical translation" ... does that mean fixed all freedoms except out-of-plane translation ? ... which ould be ok.

"would the spider have any influence on the mesh" ... no, if you mean that you have to do anything special with the mesh 'cause of the spider. but the bolt is applying load to the plate, so a finer mesh is reasonable ('cause of the stress gradients). but if you're that interested in the local stress field, you might want to model the bolt and use gap/contacts in the bore of the hole (model the bolt as a beam, with pretty rigid pie-shaped elements making the circular x-section of the bolt through the 2d mid-surface). but i don't know that this'll be much better in reality ... the model will translate unless you givee it friction which the real world has.

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