ABSTRACT
In a beam subjected to transverse loads applied within the plane of symmetry (Figure 5.1(a)), only bending moment and shear forces develop on the cross-section (Figure 5.1(b)). The bending moment and shear force are, respectively, the resultants of the normal stresses (Figure 5.1(c)) and the shear stresses (Figure 5.1(d)) on the cross-section. The deformation of the beam is characterized by the following:
• The longitudinal fibres on the top side of the beam contract (are shortened). • The longitudinal fibres on the bottom side of the beam extend (are elongated). • Between the top and the bottom sides, there is a parallel surface within which fibres
are neither contracted nor extended. • Due to the uneven elongation of the fibres, the beam exhibits lateral (transverse)
deformation that is termed as deflection.
