Nowadays it is well known that the classical Euler-Bernoulli beam theory is valid only for long
span, equivalently thin, beams. In 1921 S. P. Timoshenko proposed a new beam theory that
has been used for short, equivalently thick, beams. Unlike the Euler-Bernoulli hypothesis, the
Timoshenko beam theory supposes that the plane section originally normal to the beam middle
axis remains plane but not necessarily normal to the deformed axis, as in addition also transverse
shear deformations can occur. Thus, using this theory it is possible to analyze thicker beams
more accurately than by the classical beam theory