General Equations of the Theory of Elasticity

TLDR: In this paper, the displacement vector of a point relative to another point in the body during deformation is defined as the difference between the displacement vectors of the point and its displacement vector after deformation.

Abstract: A body is deformed when forces are applied to it; the distances between points in the body subject to the forces are somewhat different from those between the same points in the absence of the forces . The change in distance is due to displacement of one relative to another during the deformation. Let r0 be the radius vector of some point in the body (relative to some fixed point in space) before the deformation, and let r(xi) be the same after deformation. The difference between these vectors is the displacement vector of the point and is (1.1) or in coordinate form (1.2)