Solving Stress-Strain Curve: Ultimate Stress, Units Confirmation

[aaronfue]

Homework Statement

I was creating a stress-strain curve for a soft aluminum alloy (as stated in problem) and was looking to find the ultimate stress and ensure my units were all okay.

I have attached a screenshot of my graph. And a separate screenshot with the formulas.

Homework Equations

E=σ/ε
σ=P/A
ε=δ/L₀

The Attempt at a Solution

I think I have my graphs correct. I am aware of how to get the modulus of elasticity, yield strength, but the ultimate strength is confusing me on this one. It couldn't be the strength at fracture. How can I find it?

Also, if anyone could confirm that my units are set up correctly, I would greatly appreciate it.

 

[SteamKing]

Ultimate strength means the stress at fracture. Once the sample fractures, it cannot support any more stress.

Your units look OK.