foldforhold

Foldforhold is a term used in Danish and Norwegian technical literature to describe the relationship between folds in a material or structure and its resulting geometry or properties. It is typically defined as a ratio comparing a folded state to the original, most commonly the thickness after folding to the thickness before folding, but it can also refer to length, height, or stiffness depending on context. The concept appears across disciplines such as paper engineering, textiles, packaging, and geology, where folding alters mechanical behavior and geometry.

In practice, foldforhold helps quantify how folding changes performance. A higher foldforhold generally increases stiffness and resistance to compression, but can reduce flexibility and may lead to buckling if the fold pattern is unfavorable. In geology, foldforhold relates to apparent thickening due to deformation, aiding interpretation of folded rock sequences. In originative design and packaging, it informs material deployment, stacking efficiency, and load-bearing characteristics.

Measurement and calculation: foldforhold is expressed as F = t_folded / t_original, where t denotes the relevant dimension such as thickness. For an ideal sheet folded N times with each fold effectively doubling thickness, foldforhold ≈ 2^N. In real materials, factors such as finite crease quality, material shear, and buckling can cause deviations from this ideal value.

See also: folding, laminated materials, structural geology, origami.