• Support PF! Buy your school textbooks, materials and every day products Here!

Stress-strain diagram using deformation ?

  • Thread starter the_rider
  • Start date
2
0
1. Homework Statement

I have a lab report where I have to plot a stress-strain diagram for 2 beams. We apply an increasing load at midspan and record the deflection. I have to find the strain so I can plot the diagram. Also, the diagram willl be use to find the modulus of elasticity so I can use the stress = Ee

2. Homework Equations

I cannot use stress = Ee since the modulus need to be find. I know that strain = (l-lo)/lo but since it is not en elongation but a bending I don't know what's the relation between strain and deflection

3. The Attempt at a Solution

I was thinking about using trigonometry to find the change in length but I wouldn't be accurate and the error on the length will be to big to use. It's a lab report so usually it shouldn't be to complicated. I look on the internet, in all my books and didn't not find any relation between strain and deflection.

Thank you
Alex B.
 

Answers and Replies

Mapes
Science Advisor
Homework Helper
Gold Member
2,592
17
Hi Alex B., welcome to PF. I suggest you find any mechanics of materials book (Beer and Johnston is a classic) and look at the chapter on bending. You will find many useful relationships between stress and strain for a bending beam.
 
2
0
Thanks Mapes.

I found the formula i need 1/p(rho) = M(x)/EI then I find my E, then use O=Ee to find my strain.
 

Related Threads for: Stress-strain diagram using deformation ?

Replies
1
Views
2K
  • Last Post
Replies
1
Views
979
  • Last Post
Replies
3
Views
1K
Replies
4
Views
25K
Replies
0
Views
3K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
2
Views
3K
Top