A torsion box consists of two skins to carry the applied loads on either side of a core material usually constructed as a lightweight grid of thin beams. A hollow core door is probably the most commonly found example of a torsion box (stressed skin) structure. Like an I beam or truss, the idea is to use less material more efficiently. The torsion box uses the properties of its thin surfaces to carry the imposed loads primarily through tension and compensate for the tendency of the opposite side to buckle under compression by placing the web material grid closely spaced to reduce the span of the material. In part, the flat surfaces also carry the load by resisting being deformed into a complex curve just as a curved egg shell resist being flatten. Torsion boxes are also used in the construction of structural insulated panels for houses, airframe

Airframe

The airframe of an aircraft is its mechanical structure. It is typically considered to include fuselage, wings and undercarriage and exclude the propulsion system...

s, especially wing

Wing

A wing is an appendage with a surface that produces lift for flight or propulsion through the atmosphere, or through another gaseous or liquid fluid...

s and vertical stabilizer

Vertical stabilizer

The vertical stabilizers, vertical stabilisers, or fins, of aircraft, missiles or bombs are typically found on the aft end of the fuselage or body, and are intended to reduce aerodynamic side slip. It is analogical to a skeg on boats and ships.On aircraft, vertical stabilizers generally point upwards...

s, in making wooden table

Table (furniture)

A table is a form of furniture with a flat and satisfactory horizontal upper surface used to support objects of interest, for storage, show, and/or manipulation...

s and door

Door

A door is a movable structure used to open and close off an entrance, typically consisting of a panel that swings on hinges or that slides or rotates inside of a space....

s, and for ski

Ski

A ski is a long, flat device worn on the foot, usually attached through a boot, designed to help the wearer slide smoothly over snow. Originally intended as an aid to travel in snowy regions, they are now mainly used for recreational and sporting purposes...

s and snowboard

Snowboard

Snowboards are boards, usually with a width the length of one's foot, with the ability to glide on snow. Snowboards are differentiated from monoskis by the stance of the user...

s.