Deformation
Deformation - change in the size and shape of the solid body under the influence of external forces or some other influences. When deformed, the point of a solid changes its position. A point with a radius vector in deformation has a new position, that is, it will carry out the displacement. The displacement field is one of the characteristics of the deformation, but it is inconvenient for the mathematical description, since, for example, when the rod is elongated, the points are shifted very little at the beginning of it, and in the end quite a lot. Much more important is the extent to which the point of the body has shifted relative to the neighbor.