dünnwandig

Dünnwandig is an adjective in German meaning "having thin walls." It is used to describe structures whose wall thickness is small relative to their overall size or to the forces they bear. The term is a qualitative descriptor rather than a specific material classification and appears in biology, materials science, and engineering.

In biology, dünnwandig describes cells or tissues with relatively thin cell walls, which often results in a higher surface-area-to-volume ratio and greater permeability compared with thick-walled cells. In plants, parenchyma tissue is typically thin-walled, while sclerenchyma and some collenchyma tissues can be thicker. In microbiology, the term can be applied to cells with comparatively thin walls, such as certain bacteria with thin peptidoglycan layers in contrast to thicker-walled forms.

In engineering and materials science, dünnwandig refers to shells, vessels, pipes, and other structures whose wall thickness t is small compared with their radius r (often t/r << 1). Thin-walled approximations simplify mechanical analyses, yielding relations such as the hoop stress σh ≈ P r / t and the axial stress σa ≈ P r / (2 t) for pressure vessels. Thin-walled designs reduce weight and material use but can be more prone to buckling, leakage, or deformation under load.

Thickness classification is context-dependent; practical bounds vary by field, but a common rule is to consider walls thin when t/r is well below 0.1 to 0.2, though some applications use even smaller ratios.

See also: wall thickness, thin-walled pressure vessel, shell structure, cell wall.