Going from NXN 11 to 12, the release note seem to indicate that all the changes to contact are related to SOL401. However, when I try running my linear contact (SOL101) models in NXN11 and NXN12, I get significantly different answers. Often, a model will run in one but not the other. The attached model (for some reason, I needed to change this to a .txt file extension) is two plates bolted together with contact and preload. One end of a plate is restrained, and the other end of the other plate has a vertical load applied. The model runs in NXN12 (and Simcenter 2019.1), but gives a fatal error in NXN11. In this version, I used PENTYPE 2 to explicitly define the tangential and normal stiffnesses. When using PENTYPE 1, NXN12 computed a tangential penalty factor that was an order of magnitude lower than for NXN11.
Is there a default somewhere that was changed from NXN11 to 12? The discussion of the penalty factors and contact stiffnesses all look identical in the QRG. Any help would be greatly appreciated.