Elastische

Elastische is a term used to describe the property of materials to deform under load and return to their original shape when the load is removed. In physics and materials science, elasticity deals with reversible deformations and how materials store elastic energy.

In linear elasticity, the stress tensor and the strain tensor are related through constitutive laws. For isotropic materials, Hooke's law reduces to simple scalar relations using the Young's modulus, the shear modulus, and the bulk modulus, with Poisson's ratio describing lateral contraction. In general, elasticity is described by an elasticity tensor, which accounts for direction-dependent (anisotropic) behavior.

The study of elasticity has wide applications: designing structures and mechanical components, modeling seismic wave propagation, analyzing the mechanical behavior of biological tissues, and developing elastomeric polymers and fabrics (such as elastane) used in clothing. The term is also common in Dutch and German, where it simply denotes elastic properties.

Historically, elasticity theory originated with Hooke's law, which states that strain is proportional to stress within the elastic limit. In the 18th and 19th centuries, mathematicians like Cauchy, Navier, and Lame extended the theory to three-dimensional bodies and laid the groundwork for modern continuum mechanics.

Etymology: elasticity derives from Greek elastos meaning able to be stretched, via Latin elasticus, and enters scientific usage through English and other languages.