How to Calculate Young's Modulus from a Non-Linear Stress-Strain Graph

[TyErd]

Homework Statement

Question simply asks to calculate the Youngs modulus. I've attached the question.

Homework Equations

Youngs Modulus = (change in stress)/(change in strain)

The Attempt at a Solution

okay, what i did was simply find the gradient between each of the points. However they were all different gradients, which means the graph isn't linear (i think). So then how do i solve it?

 

[PeterO]

Homework Statement

Question simply asks to calculate the Youngs modulus. I've attached the question.

Homework Equations

Youngs Modulus = (change in stress)/(change in strain)

The Attempt at a Solution

okay, what i did was simply find the gradient between each of the points. However they were all different gradients, which means the graph isn't linear (i think). So then how do i solve it?

I believe Youngs modulus can only be calculated for stress-strain that remains below the elastic limit - ie the first straight part of the graph.

EDIT: btw, I don't see the question attached, but hopefully this will help anyway.

 

[TyErd]

sorry about that, I've attached the question now.

 

[PeterO]

sorry about that, I've attached the question now.

What did you make of the statement in the first sentence?

 

[TyErd]

Oh i get it, the first data point would be 0 stress 0 strain and the gradient between 0,0 and the 1st data point is the same as the gradient between the first data point and the second data point but different from the 2nd and 3rd. I get it, thank you!

 

[PeterO]

Oh i get it, the first data point would be 0 stress 0 strain and the gradient between 0,0 and the 1st data point is the same as the gradient between the first data point and the second data point but different from the 2nd and 3rd. I get it, thank you!

well done.