mechanical engineering Mechanical engineering is the study of physical machines that may involve force and movement. It is an engineering branch that combines engineering physics and mathematics principles with materials science, to design, analyze, manufacture, ...

, stressed skin is a type of rigid construction, intermediate between

monocoque Monocoque ( ), also called structural skin, is a structural system in which loads are supported by an object's external skin, in a manner similar to an egg shell. The word ''monocoque'' is a French term for "single shell". First used for boats, ...

and a rigid frame with a non-loaded covering. A stressed skin structure has its compression-taking elements localized and its tension-taking elements distributed. Typically, the main frame has rectangular structure and is triangulated by the covering.

Description

A framework box can be distorted from being square, so it isn't rigid by itself, however adding diagonals that take either tension or compression fixes this, because the box cannot deviate from right angles without altering the diagonals. Sometimes flexible members like wires are used to provide tension, or rigid compression frames are used, as with a Warren or

Pratt truss A truss bridge is a bridge whose load-bearing superstructure is composed of a truss, a structure of connected elements, usually forming triangular units. The connected elements (typically straight) may be stressed from tension, compression, or ...

, however both these are full frame structures. When the skin or outer covering is in tension so that it provides a significant portion of the rigidity, the structure is said to have a stressed skin design. This may also be referred to as semi-monocoque, and overlaps with

, which has less framing, sometimes only including longitudinal or lateral members, and also overlaps with rigid frame structures where a minor portion of the overall stiffness may be derived from the skin. This method of construction is lighter than a full frame structure and not as complex to design as a full monocoque.

Examples

Examples include nearly all modern all-metal

airplanes An airplane or aeroplane (informally plane) is a fixed-wing aircraft that is propelled forward by thrust from a jet engine, propeller, or rocket engine. Airplanes come in a variety of sizes, shapes, and wing configurations. The broad spectr ...

, as well as some railway vehicles,

bus A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a road vehicle that carries significantly more passengers than an average car or van. It is most commonly used in public transport, but is also in use for cha ...

es and

motorhome A motorhome (or motor coach) is a type of self-propelled recreational vehicle (RV) which offers mobile living accommodation. Features Motorhomes usually have sleeping spaces for two to eight people. Each sleeping space is either fixed or conv ...

s. The London Transport

AEC Routemaster The AEC Routemaster is a front-engined double-decker bus that was designed by London Transport and built by the Associated Equipment Company (AEC) and Park Royal Vehicles. The first prototype was completed in September 1954 and the last on ...

incorporated internal panels riveted to the frames which took most of the structure's shear load. Automobile unibodies are a form of stressed skin as well, as are some framed buildings which lack diagonal bracing. * Dornier-Zeppelin D.I : ''first all-metal stressed skin fighter and first with stressed skin wings'' (1918) * Short Silver Streak : ''first all-metal British stressed skin aircraft'' (1920) * Zeppelin-Lindau (Dornier) Rs.IV : ''first aircraft with an all-metal stressed skin fuselage to fly'' (1918) * Zeppelin-Staaken E-4/20 : ''first all-metal stressed skin four-engine airliner'' (1919) * Northrop Alpha : ''first American all-metal stressed skin aircraft'' * GM New Look bus : ''stressed-skin bus, over 44,000 built since 1959, and many still in service''

References

Notes

External links

Stressed Skin

Wood to Metal: The Structural Origins of the Modern Airplane
{{Aircraft components Automotive technologies Aircraft skin Structural engineering