Elongation is the deformation of a component in relation to the undeformed geometry. The strain is therefore dependent on the acting force and the material parameters. 



The acting forces can be mechanical or thermal forces. There is both positive and negative stretching. This means that the body becomes either longer (stretching) or shorter (compression). The corresponding behavior of materials under given forces can be calculated very precisely using modern simulation technologies such as the finite element method (FEM). This means that the behavior of components or complete products under elongation forces can be calculated in advance without the need for a physical test setup.