Hi @travis.potier
The difficulty with the beam preload in the nonlinear analysis is that the full load is applied at time 0. If there were a way to ramp the preload (there's a suggestion!), then you could get it to converge.
There may be other ways to accomplish the preload depending on the situation. If the geometry were like the article (a band around a drum), shrink fit contact could be used. (In a nonlinear analysis, the shrink fit is applied "gradually" to allow it to converge. It usually takes 7 or 8 increments to stabilize.) If shrink fit is not appropriate, you could use thermal contraction to cause the beam to "tighten". The first subcase would include only the thermal load to contract the beam, and you would need to do a test to determine the temperature change that is necessary to get the preload. (A hand calculation would get you close to the amount of contraction needed, but the compression of the rest of the model means that you need more thermal contraction to get the desired preload than indicated by the hand calculation.)
John Holtz, P.E. Global Product Support
Autodesk, Inc. If not provided already, be sure to indicate the version of Inventor Nastran you are using!"The knowledge you seek is at knowledge.autodesk.com" - Confucius 😉
