Stressed skin

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In mechanical engineering, stressed skin is a type of rigid construction, intermediate between monocoque and a rigid frame with a non-loaded covering.

Geodesic domes, structures built up of tetrahedrons, early 20th century cars, some 21st century trucks (and vehicles intermediate between cars and trucks), most chairs, etc. have their structure concentrated in a small part of their surface. These structures may or may not be covered, but the covering contributes little strength to the larger structure.

Small boats, modern racing cars, modern airplanes, and insects use structural elements that are spread, nearly equally, over much of their surfaces.

A stressed skin structure (https://www.cnet.navy.mil/nascweb/sas/stress.htm) has its compression-taking elements localized and it tension-taking elements distributed. Typically, the main frame has rectangular structure and is triangulated by the covering.

By themselves, the edges of a box are not rigid because the box can be skewed without changing their lengths. Adding diagonals, even if they take only tension and not compression, fixes this because the box cannot deviate from right angles without stretching some of the diagonals. Sometimes thin flexible members like wires are used. When a covering, which usually serves other purposes as well, is used, the structure is said to have a stressed skin design.

Examples include some early airplanes, the Lotus Seven, moderately light outdoor rubber powered model airplanes, some early racing cars and most tents.