# PARAM, EPZERO

Bulk Data Entry An upper bound for the stiffness ratio below which a degree of freedom will be regarded as an AUTOSPC candidate.

Parameter Values Description
EPZERO < Real ≥ 0 >

No default

If some of the three translational and three rotational degrees of freedom of a node have stiffness ratios below EPZERO, they will become AUTOSPC candidates.

Stiffness ratio calculation:

For a given node, the three translational stiffness eigenvalues and three rotational eigenvalues will be calculated. The largest of the translational eigenvalues will be used to scale the three translational stiffness eigenvalues. Similarly, the largest of the rotational eigenvalues will be used to scale the three rotational stiffness eigenvalues.

If PARAM,EPZERO is input without a value, then OptiStruct will error out.