Bending moment in an axis doesn´t match

Click For Summary
SUMMARY

The discussion centers on discrepancies in bending moment calculations for an axle subjected to forces from gears. The user is attempting to reconcile results obtained through moment equilibrium with those derived from shear force and bending moment diagrams. Key variables include the forces applied (in force-pounds), the axle diameter (D4), and the reactions at the bearings (Raz, Ray, Rbz, Rby). Additionally, the user seeks clarification on why the torsion diagram indicates constant torque despite variations in the circular section.

PREREQUISITES
  • Understanding of shear force and bending moment diagrams
  • Knowledge of moment equilibrium principles
  • Familiarity with torsion in mechanical systems
  • Basic concepts of axial loading and reactions in beams
NEXT STEPS
  • Study the derivation of shear force and bending moment diagrams in structural analysis
  • Learn about the relationship between shear forces and bending moments
  • Investigate the principles of torsion in circular shafts
  • Explore advanced topics in moment equilibrium for complex loading scenarios
USEFUL FOR

Mechanical engineers, structural analysts, and students studying mechanics of materials who are looking to deepen their understanding of bending moments and torsion in structural components.

Guidestone
Messages
93
Reaction score
5
Hey guys, first of all, this isn't a homework question, I just want to know why the results are what they are. I've been trying t obtain the same numbers using moment equilibrium but they still don't match. This is the example:

upload_2016-7-9_23-33-15.png

W are the forces applied by the gears in force-pounds. The gears are located at the sides of the thickest part of the axle which is the diameter D4. The distances in inches are located below where the letters are.
upload_2016-7-9_23-38-22.png

To obtain the graphs analysing x-y axis and z-x axis is necessary. The reactions in the bearings are Raz, Ray, Rbz and Rby. These are used to obtain the shear force diagrams and the bending moment diagrams. I'm unable to obtain the values in the bending moment diagrams. Also, if you could tell me why the torsion diagram (the first one above with the number 3240 on it) says torque is constant despite the change in the circular section I would really appreciate it.
Thank you guys!
 

Attachments

  • upload_2016-7-9_23-36-59.png
    upload_2016-7-9_23-36-59.png
    46.6 KB · Views: 531
  • upload_2016-7-9_23-38-6.png
    upload_2016-7-9_23-38-6.png
    43.3 KB · Views: 545
Engineering news on Phys.org
Why would you expect torsional moments to change at a change in cross section? Would you expect shears or bending moments to change?
Please explain your difficulty in determining moments from the shear diagram.
 

Similar threads

Solving Shear Force and Bending Moment at Reaction Point R
  • · Replies 11 ·
Replies
11
Views
3K
Engineering Distance is a problem -- find shear force and bending moment diagram
  • · Replies 2 ·
Replies
2
Views
3K
Loader Boom maximum bending moment
  • · Replies 2 ·
Replies
2
Views
2K
Deriving Bending Moment Diagrams from Shear Force Diagrams
  • · Replies 12 ·
Replies
12
Views
10K
Shear force and bending moment
  • · Replies 16 ·
Replies
16
Views
4K
Shear force diagram and bending moment diagram
  • · Replies 10 ·
Replies
10
Views
3K
Producing a shearing force diagram and bending moment curve
  • · Replies 13 ·
Replies
13
Views
4K
Correct Shear Force and Bending Moment Diagrams for Beam Analysis
  • · Replies 1 ·
Replies
1
Views
2K
Help with understanding Shear Force and Bending Moment
  • · Replies 2 ·
Replies
2
Views
3K
Shear Force and Bending Moment Diagram
  • · Replies 1 ·
Replies
1
Views
2K