User Area > Advice
Typical warning message found in the LUSAS Solver text output (*.OUT) file:
***WARNING*** SOME ELEMENTS WITH ECCENTRIC GEOMETRIC PROPERTIES HAVE BEEN ASSIGNED A NONLINEAR MATERIAL – STATE VARIABLES SUCH AS PLASTIC STRAINS WILL BE EVALUATED USING STRESS RESULTANTS COMPUTED AT THE NODAL LINE AND NOT AT THE BEAM CROSS SECTION (KBTS6 PROCESSOR)
Most common causes & links to solutions
This warning is to inform the user that plastic strains are evaluated using stress resultants computed at the nodal line and not at the beam
eccentric cross-section.
Using the Stress Resultant material model for beams, the whole section will yield instantaneously and, as such, cannot be considered to yield
only at an extreme fibre location with the section therefore partially yielded. The whole cross-section is considered as
either
fully elastic, or completely plastic. For this reason, stresses at extreme fibre locations
may exceed the yield stress. For further details of this material model and its yield
criterion, please see:
Theory Manual Volume 1 > Chapter 4 : Constitutive
Models > 4.3 Plasticity Models for Beams and Shells > 4.3.2 Resultant Model
The plastic strains will be given at the nodal line. The yield criterion considers axial forces, moments, torsions and shears
where the values computed at the nodal line rather than the neutral axis
will be used for checking the yield. Moment and force values at the
neutral line could be different to the values at the eccentric
section and thus the input plastic section properties and the values
used could cause some approximation in the initiated yield.
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