Systeem van krachten en koppels

Consider a structural member having a system of various forces and couple moments.

To move the force to a point O that is not lying on the line of action of force, a couple with a moment equal to the moment of the force about O is added.

According to the principle of transmissibility, a force acting on a body is a sliding vector that can be applied at any point along its line of action.

Since a couple moment is a free vector, it can be directly moved to point O.

The resultant force equals the sum of all forces and is independent of the point's location.

The resultant couple moment equals the sum of all the couple moments and the moments of the forces about point O and depends on the point's location.

The resulting force and couple moment acting at point O produce the same external effects as the original force and couple moment system.

This method can be generalized for a number of forces, their components, and couple moments.