Steel Interchange

Peak Stress

Answer

No. Assessment of results employing finite-element modeling techniques is really a matter of engineering judgment. The AISC Specification limit states are based on use of average stresses in most cases; not peak stresses as may result from a finite element analysis. When such is used, engineering judgment is involved as to how this may relate to the Specification parameters, and is beyond the scope of the Specification. Localized stresses in members are assumed to redistribute through inelastic deformation thus justifying the use of average values. Where such localized stresses can be cause for failure, such as at net sections, the Specification accounts for them separately. Please note that the AISC typically deals in member strength values that correspond to the entire member cross-section, while finite element programs are likely to give stress vales that vary across the member cross-section.

Kurt Gustafson, S.E., P.E.