Statics of **inextensible** chains.

The principle of virtual work is specially convenient in the theory of frames (~ 6), since the reactions at smooth joints and the stresses in **inextensible** bars may be left out of account.

Statics of **Inextensible** Chains.The theory of bodies or structures which are deformable in their smallest parts belongs properly to elasticity.

The case of **inextensible** strings or chains is, however, so simple that it is generally included in expositions of pure statics.

The statement may be extended to a system of rigid bodies, provided the mutual reactions consist of the stresses in **inextensible** links, or the pressures between smooth surfaces, or the reactions at rolling contacts (~ 9).