Tips for Plotting Shear and Moment Diagrams
by Scott Volner

1. Sign Convention

   1. If you're working left to right then positive shear tips the "beam" clockwise.

   2. Positive Moment tends to make the beam flex into a "smiley face".

2. The VALUE of the shear is the SLOPE of the moment curve.

3. The VALUE of the distributed load is the negative SLOPE of the shear curve.

4. The area under the shear curve between two points is equal to the change in magnitude of the Moment.

5. The area under the load curve between two points is equal to the change in magnitude of the Shear.

6. When the shear curve hits zero (intersects the X axis) the Moment curve hits a min or a max. (slope of M=O)

7. A negative sloped shear curve indicates a concave down Moment curve.

8. A positive sloped shear curve indicates a concave up Moment curve.

9. Equations

   1. dV = -w(x) dx

   2. dM = V(x) dx

   3. These equations are only good between the discontinuities.