Study the following shear moment diagram to understand better the value of shear force and bending moment. Shear and bending moment diagrams are analytical tools used in conjunction with structural analysis to help perform structural design by determining the value of shear force and bending moment at a given point of a structural element such as a beam. Give a look at the following examples of the diagram below.
These Shear Moment Diagrams are used to describe the change of shear forces and moments. It is important to know how the shear forces and bending moments vary along the length of a beam that is being designed. Employing these diagrams, the maximum and minimum shear and moment are easily identified and located. Constructing shear and moment diagrams is similar to finding the shear and moment at a particular point on a beam structure.
When constructing shear and moment diagrams, the sign convention is important so viewers will know what direction the beam is bending or shearing. Generally, it is assumed that a positive moment causes a beam to bend downward as shown in the diagram. A positive shear will skew the beam with the left side going up and the right going down, as shown in the diagram.
If the shear force is constant over an interval, the moment equation will be in terms of x (linear). If the shear force is linear over an interval, the moment equation will be quadratic (parabolic). A shear force diagram can be constructed from the loading diagram of the beam. Learn about shear and moment diagrams using the examples that we have provided in the list above!