The free body diagram is the representation often used by physicists and engineers to analyze the forces acting on a free body. diagram facilitates the identification of the forces and moments that must be taken into account to solve the problem. They are also used for the analysis of the internal forces that act on structures.[1]​[2]​.

Contenido

Un esquema del cuerpo en cuestión y de las fuerzas que actúan sobre él deben ser representadas como vectores. La elección del cuerpo es la primera decisión importante en la solución del problema. Por ejemplo, para encontrar las fuerzas que actúan sobre una bisagra o un alicate,es mejor analizar solo una de las dos partes, en lugar del sistema entero, representando la segunda mitad por las fuerzas que ejerce sobre la primera.

Internal forces developed in structural elements

To design a structural or mechanical element it is necessary to know the load that acts within it to ensure that the material can resist this load. Internal loads can be determined by the section method, imaginary sectioning or cutting a section perpendicular to the axis of the beam. The internal loads acting on the element will be exposed and become external in the free body diagram of each segment.

What to include

The body outline should reach only the necessary level of detail. A simple outline may be sufficient and sometimes, depending on the analysis to be carried out, one point may be enough.

All external forces are represented by appropriately labeled vectors. The arrows indicate the direction and magnitude of the forces and, as far as possible, should be placed at the point where they are applied.

Only forces acting on the object should be included, whether frictional, gravitational, normal, drag "Drag (physics)") or contact. When working with a non-inertial reference frame, it is appropriate to include fictitious forces such as centrifugal forces.