What is bending moment?
bending moment at a section is the algebraic sum of the moment of all the forces (on any one side of the section) about the section.
Bending moment With "bending" you really mean the bending moment. The bending moment in an inner stress within a member (usually beam) that allows it to carry a load. The bending moment doesn't say anything about how much a beam would actually bend (deflect). Deflection Deflection measures the actual change in a material you could call "bending." It measures the physical displacement of a member under a load.
A point of contra flexure occurs where the bending moment in a beam changes its sign (i.e. from +ve to -ve or -ve to +ve) So, obviously at the point of contraflexure the bending moment is zero. But note that the bending moment can be zero without changing its sign. So, at the point of contraflexure the bending moment has to be zero and the bending moment must change its sign as well.
bending moment varies with the distance & the load carried by the beam. And also there is a hogging behavior and a sagging behavior occurs in the beam. According to the sign convention hogging and sagging bears opposite signs.(- & +). So if we are asked to find the maximum bending moment whether it is sagging or hogging we should consider the maximum value without considering the sign. That value is called maximum absolute bending…