When creating a spring property with a user-defined curve "Force vs Displacement" for the
stiffness, typically the end of the curve has a very high slope to deal with very
high compression. In this case, the following warning is often received with
Radioss
Starter.
WARNING ID: 506
** WARNING IN SPRING PROPERTY
** WARNING IN SPRING PROPERTY SET ID=XXX
STIFFNESS VALUE 100 IS NOT CONSISTENT WITH THE MAXIMUM SLOPE (4550)
OF THE YIELD FUNCTION ID=X
THE STIFFNESS VALUE IS CHANGED TO 1000
This warning comes from the fact that the slope of the input curve (the stiffness) is not
consistent with the initial stiffness. If the maximum slope of the curve (the
maximum stiffness) is greater than the initial stiffness, unloading in the zone of
maximum slope will be false (Figure 1). To obtain proper behavior, Radioss Starter modifies
the initial stiffness according to the maximum slope. Figure 1. Stiffness Not Consistent
