Given a finite element, ABCD, which is subject to a set of stresses, it is possible using mechanics theory to cut that element along an arbitrary line, EF, and resolve the forces at the cut surface.

However, the forces of adjacent finite elements obtained this way are not balanced (i.e., not in equilibrium) and the stress values are discontinuous across element boundaries.

STAAD.Pro has stress result options for cut lines which employ a method of mathematically processing the FEA stress results which are then in equilibrium against the cross-section forces and are continuous across element boundaries. The cut line coordinate system, STR, is used (i.e., a local coordinate system with S as the axis along the cut line, T in the plane of the elements, and R normal to those elements).

The following nomenclature is used for the cut line-oriented results available in STAAD.Pro:

Stresses along a cut line for "-Line" stress types

St

Normal stress perpendicular to the cut line, σ_t.

Sts

Shear stress along the cut line, τ_t.

Mt

Bending moment along the cut line, M_t.

Mts

Bending Moment about the T axis. This is in the plane of the plate and perpendicular to the cut line (i.e. the S axis).

Qt

Out-of-plane shear, Q_t

Forces listed in the table when these results are selected are given in the in a coordinate system relative to the cut line (i.e., "FS" is along the cut line, "FT" is in the plane of the element, and "FR" is normal to the element). This is indicated by the "-Line" suffix of the results.

Forces along a cut line for "-Line" stress types

Fs

Resultant force along the cutline

Ms

Resultant moment about the cutline

Ft

Resultant force perpendicular to the culine in the plane of the plate

Mt

Resultant moment about the line perpendicular to the cutline in the plane of the plate

Fr

Resultant force perpendicular to the cutline out of the plane of the plate

Mr

Resultant moment about the line perpendicular to the cutline out of the plane of the plate