Theoretical Modeling of a Beam with Variable Section and Finite Rigidity in A Fatigue Testing Machine to Verify the Bending Moment Produced in The Central Portion of The Smallest Diameter of The Beam Subjected to External Loads

There is a bending fatigue machine where it is detected that when loads are applied, the theoretical model of the beam with which the machine was designed to obtain the bending moment does not coincide with the real measurements of the bending moment obtained experimentally and the specimen does not break, to determine the correct theoretical modeling applicable to this fatigue machine, the following static models are proposed, and the theoretical results are obtained through computer simulation.  The bending moment values ??produced by the applied loads are verified with measurements through the Hooke and Navier law using strain gages, the analysis of the different modeling is carried out and those that are closest to the real model obtained experimentally are analyzed