Graph Bending Moment Equation in Excel/Matlab

Click For Summary

Discussion Overview

The discussion revolves around how to graph the bending moment equation, specifically the equation σ = MC / I, using software tools like Excel or MATLAB. Participants explore the relationship between the variables involved and the appropriate methods for plotting the graph.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • One participant seeks guidance on graphing the bending moment equation and mentions having values but lacking knowledge on how to create the graph.
  • Another participant suggests revising bending moment concepts and provides a link to resources on bending moment diagrams.
  • A different participant offers a MATLAB approach, detailing how to define x-coordinates and the variables M, C, and I, and how to plot σ as a function of x.
  • One participant questions the initial poster's understanding of the bending moment, pointing out that the formula provided may not directly relate to bending moment plotting.

Areas of Agreement / Disagreement

There is no consensus on the correct interpretation of the equation σ = MC / I in the context of bending moments, as some participants challenge the relevance of the formula to bending moment graphs.

Contextual Notes

Participants express uncertainty regarding the definitions of the variables σ, M, C, and I, and how they relate to the bending moment. There are also assumptions about the constancy of C and I along the beam's length that remain unverified.

aaalanc
Messages
1
Reaction score
0
how can i graph the equation of the bending moment?
The equation is: σ = MC / I and i want to graph in excel or matlab, , so i know that the graph is a straight line, and i have the values, but i don't know how draw the graph
 
Physics news on Phys.org
let's say you've got a set of x-coordinates, from x=0 to x=L. If you're using matlab, type the following:

x=linspace(0,L,L)

where L is the total length of the beam. That will give you an entire array of x-values.

I'm assuming M is dependent upon x. You should have some sort of equation already. C and I are constant the whole length of the beam, I hope. (If not, then they still depend on x, and you can simplify MC/I into one big function of x). So now, define M, C, and I in the program:
M= whatever
C= whatever
I = 1/12*whatever*whatever^3

Then, define Sigma in terms of M, C, and I (which are already defined in terms of x).

Sigma = M*C/I

Finally, you can plot the results by typing:

plot(x,Sigma)
 
Did you do as I suggested and revise what a bending moment is?

You say you want to plot a graph of bending moment but your formula is for something different.

What is sigma, M, C and I in your formula and how is a plot of sigma v x a plot of bending moment?
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 1 ·
Replies
1
Views
4K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 12 ·
Replies
12
Views
7K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 2 ·
Replies
2
Views
3K