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6 DIRECT CROSS BENDING

6.1 Bending moment and shear force

Direct cross bending is called a kind of deformation when in the
cross-sections of the rod there may be only two internal force
factors - shear force and bending moment acting in the principal
plane of inertia of the rod.
Recall that the principal plane of inertia - a plane passing
through the axis of the rod and one of the principal central axes of
inertia of its cross section (fig. 6.1).

Figure 6.1

The rod that works at a bend, is called the beam. The main
feature of deformation of beam bending is changing the curvature
of its axis. The word "direct" indicates that the curvature of the
axis of the beam is in its principal plane. The word "cross"
indicates that the external forces act perpendicular to the axis of
the beam.
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