The Differential Relationship among Shearing Force,Bending Moment and Load Collection in the Theoretical Mechanics

The first derivative of shearing force is equal to the load collection of the beam(loading downward stands for negative value),The first derivative of bending moment is equal to the shearing force.The load bearing shearing force and the bending moment make up the load collection of the beam.The differential relations of the load collection,the shearing force and the bending moment tell us,the slope of one point in the shear diagram is equal to the load collection which functions on the correspondent point of the beam.The slope of one point in the bending moment diagram is equal to the shearing force in the corresponding section of the beam.But the convexity-concavity of a certain curve in the moment diagram is determined by the distributed load direction of this curve.