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Modelling a pre-loaded stud, with additional forces

Question asked by Doug Rawlings on Sep 18, 2013
Latest reply on Sep 23, 2013 by Jared Conway

Hello all,


I'm trying to model a situation where a stud runs through the centre of a cylindrical boss, holding that boss onto a fixed support. At the end of the boss a load is applied acting in the radial direction with respect to the stud axis. I'm trying to find when the joint between the boss and the support starts to come apart.


So far I've been trying to do this by putting some interference between the nut and the top of the boss, then defining this as a shrink fit contact.


The fixed component is fixed pretty well with fixed geometry constraints.


Then I apply a load at the edge of the boss.


When I run this with very low forces then it looks fine but it only takes a very small amount of force for the joint to come apart, much less than my spreadsheet calcs suggest. And then it shows much greater deflection than is expected.


So my question is: does this sound like a valid way of modelling the preload on the stud? My concern is that it is getting confused with the deflection occuring due to the external force.


Any help would be appreciated,