Forces Stresses and Couples

Abstract

In the mechanics of particles it is usually proved that a system of forces, say f ₍₁₎,f ₍₂₎,...,f _(n) acting on a system of particles M₁,...,M_n may be reduced to the resultant force

$$$$

(6.1)

and to the resultant couple, which is defined with respect to a pole 0 by the expression

$$$$

(6.2)

where r _i are position vectors of the particles M_i with respect to 0. In continuum mechanics an immediate generalization is insufficient to describe all the forces and couples which appear, even if the suitable assumptions are made for the transition from a discrete system to a continuum model.