Verformungs

Verformung (English: deformation) refers to the change in shape or size of a body caused by external forces, temperature changes, or phase transformations. It covers both temporary elastic changes and permanent plastic changes and is a central concept in physics, materials science, and engineering.

Deformation is typically classified as elastic—reversible—and plastic—permanent. Elastic deformation disappears when the load is removed; plastic deformation remains, often through dislocation motion or yielding in crystalline materials. Some materials also exhibit viscoelastic or time-dependent creep under sustained load or temperature changes.

Quantities describing deformation include strain, which measures relative changes, and stress, the internal force per area. In small, linear elastic regimes, Hooke's law relates stress and strain through elastic moduli such as Young's modulus, shear modulus, and Poisson's ratio. For large deformations, finite-strain formalisms use the deformation gradient tensor to describe local changes.

Mechanisms and applications vary by material: dislocation motion underlies plastic flow in metals, while chain mobility governs deformation in polymers. Practical importance arises in forming processes (rolling, forging, extrusion), structural design, and geophysics, where tectonic strain shapes the Earth's crust.

Measurement and modelling: tensile tests determine properties; digital image correlation and extensometers track strain; and finite element analysis models complex deformation in structures and devices. In German-language contexts, Verformung is the term, with the stem Verformungs appearing in compounds such as Verformungsgrad (degree of deformation) or Verformungsenergie (deformation energy).