Considering geometric simpliﬁcations on the general case of solid bodies, the discipline of
strength of materials studies one-dimensional linear elastic models. Generally, it studies the internal
forces and deformation of such one-dimensional structural elements as bars, beams, and shafts. To
this purpose, it is assumed that any applied load deforms the body only, without any rigid body
motion. In this context, many expressions are determined to calculate the stresses and strains in
structures which are composed of these basic structural elements. Therefore, a one-dimensional
description of general solid mechanics concepts is considered.