What is a cantilever?

A cantilever is a rigid structural element that is supported on another element only at one end, thus leaving much of its surface with no apparent point of support. One of the most common structural elements in cantilevers are cantilever beams; however, cantilevers can also be built with lattices or forging.

The most everyday example of cantilever beams are balconies one houses and buildings.

How does a cantilever beam withstand loads?

Mechanically, the loads supported by the cantilever are transmitted to the supporting element by means of a moment, producing a shear stress.

The loads of a cantilever beam may be:

• Permanent, variable, or accidental
• Static or dynamic
• Live or dead
• Point or distributed

None of these charges is exclusive of the others, and structural analysis requires taking them all into account as well as their support reaction – that is, the reaction of the element on which the beam is supported.

The main deformation that occurs in cantilever beams is flexion (which, in turn, causes tensile and compressive forces). Different mathematical models of these elements can be used to project their behavior, depending on the particular characteristics of each structure and its applications. Some of the models are:

• Euler-Bernoulli beam theory: theoretically simplifies the mechanics of deformable solids to calculate the stresses and deformations of the beams.
• Clapeyron’s theorem or the theorem of three moments: it follows from the beam flexion theory and is used to solve some hyperstatic flexion problems.
• Timoshenko Theory: it works like the Euler-Bernoulli theory but does not disregard the shear stress with respect to the moment of flexion, so it uses more complex equations applicable to the elastic curve of short beams; it is highly useful for cantilevered beams.

What applications does the cantilever beam concept have outside the world of construction?

The structural concept of the cantilever beam has other practical applications in diverse fields; some of these include:

• Electromechanics: transducers for atomic force microscopes capable of detecting forces of the order of Nanonewtons.
• Medicine: diagnostic biosensors.
• Analytical chemistry: the beams in micro-cantilevers are coated with receptors and act as sensors or vibrating elements that are compared to fixed parameters to obtain specific chemical information. 
• Logistics: fixed or portable storage systems, such as tool boxes. 
• Aviation: the wings of airplanes.
• Tourism: panoramic tours, some as famous as the Grand Canyon Skywalk.