Beams are one of the most common structural elements. Perhaps bridges and buildings are the most visible applications of beams, but beams are found everywhere — from airplane wings to automobiles to furniture to retaining walls to robot arms. Any component that bends in response to a load is acting as a beam.
Since beams are so useful and so prevalent, engineers are frequently required to analyze the effects that loadings create in a beam so that the beam may be properly designed. An essential skill needed for this analysis is the ability to construct shear-force and bending-moment diagrams for the beam and loading.