stressedskin

Stressed-skin, or stressed-skin construction, is a structural approach in which the exterior skin of a shell or fuselage carries a substantial portion of the primary loads, working in combination with internal framing to resist bending, torsion, and shear. The skin is not merely a covering but a load-bearing element that distributes stresses across its surface.

Most stressed-skin structures use lightweight materials and stiffeners such as stringers and frames. The skin, often in tension, is stiffened to prevent buckling under compressive loads. The internal framework provides shape and additional pathways for load transfer, creating a semi-monocoque or monocoque configuration depending on how much skin carries load.

The concept emerged in early 20th century aviation as an evolution from wooden frames and fabric coverings toward metal skins. In a monocoque design the skin bears most loads with minimal internal frames, whereas semi-monocoque uses a combination of skin and internal members. The term "stressed skin" became common to describe these load-bearing skins.

Materials commonly used include aluminum alloys in aviation, with composite skins in modern aircraft. Shipbuilding and automotive industries have employed stressed-skin configurations with wood or steel skins and internal frames. Manufacturing methods emphasize skin integrity, fastener arrangements, and fuel or pressure containment in fuselages.

Its main advantages are high strength-to-weight ratio, smooth outer surfaces for aerodynamics, and efficient load distribution. Limitations include complexity of design, cost, susceptibility to skin buckling, and challenges in damage tolerance and repair.

Contemporary airliners such as the Boeing 737 and Airbus A320 use semi-monocoque stressed-skin structures, while older airframes and some military designs employed monocoque approaches. The concept remains central to light aircraft and many ship hulls.