In my plasticity analysis, issuing KUSE,-1 gives more accurate results
than the KUSE,0 default, even if I have large deflection (NLGEOM,ON)
turned on. Is this a known error?
Actually, this is not an error at all. The default KUSE setting for
plasticity uses the ELASTIC stiffness at the start of each substep.
Issuing KUSE,-1 can give slightly different results, as it uses the
TANGENT stiffness (based on the last time point's plasticity status)
instead. The default setting is designed to facilitate unloading
situations. Tightening the TOLER parameter on the CNVTOL
command will improve the results obtained by the default setting.