Hi there,

     I am running a study on a rear upright.  The geometry of the rear is almost identical to that of the front, assembly-wise.  The only difference would be the geometry of the model, more external loads, and only one more model included in the simulation.  I had little to no difficulty running the study on the front assembly, but I am having a lot of difficulty doing the same for the rear.  The solution times are either much higher(when the simulation is successful) or the study does not finish entirely.  I cannot understand why.  There is little to no difference in the contact restraints, loads, and fixtures applied to the model.  In fact, I am using a coarse mesh to try and reduce solution times, and this assembly has less than half the number of elements/degrees of freedom than the front assembly but much higher solution times!  I have also carried my study from the ground up, adding components and making changes little by little to isolate what the issue might be.  The only issue I found was using bolted connections.  I have a no pentration component contact between the two faces that are bolted together, yet I still get a prompt informing me that "contact restraints are not defined between bolted connectors".  I manually implemented conact sets rather than a component contact (running out of ideas), and the simulation failed.  I then used real bolts, no penetration component contact, and received a prompt saying "iteration stopped, model may have inadequate fixtures".  Not making sense to me, and I'm running out of ideas...

Any thoughts about why this might happening?

Thanks