Euler-Bernoulli Beam Theory
Euler–Bernoulli beam theory (also known as engineer's beam theory or classical beam theory) is a simple method to calculate bending of beams when a load is applied. This applies to  small deflections (how far something moves) of a beam without considering effects of shear deformations. Therefore, it can be considered a special case of the Timoshenko beam theory. It was first introduced around 1750. It gained popularity during the development of the Eiffel Tower and the Ferris wheel in the late 19th century. After that, it was used in many engineering fields including mechanical engineering and civil engineering. Although other advanced methods have been developed, the Euler-Bernoulli beam theory is still widely used because of its simplicity.