How Do You Calculate Elastic Modulus and Strengths from a Stress-Strain Curve?

[Name:riley]

Hello I'm having trouble wrapping my head around finding things from stress strain curvesI need to find:
Elastic modulus (Young’s modulus)
•Yield strength
•Tensile strength
•Uniform and total elongation (ductility)

elastic modulus I think is 1240/0.02 = 62000

but I'm unsure of how to find the others.

Thank you to anyone who helps out.

 

[billy_joule]

No, that is not the Youngs modulus.

Can you define any of the terms in your own words? i.e. do you know what you are looking for?

 

[Name:riley]

Thank you for your response

I am OK with yield and tensile strength it turns out.

I know what the elongation is and understand the formula Lf - Lo/Lo I just don't understand where to get the lengths from in the curve, I believe the strain is the elongation of the material but don't know where to get the original an final lengths from. Either from uniform at the 0.2% point or the total elongation.

The elastic modulus is the measure of the elasticity of the material, I know that is measured form 0 to 0.02 ( the 2% rule) of the strain as this is the beginning of the plastic region. As E= stress/strain I thought but it seems that's not the case.

I hope these explanations are satisfactory, I understand why you asked for them I guess I should have showed more of an effort to find the answers.

 

[SteamKing]

Thank you for your response

I am OK with yield and tensile strength it turns out.

I know what the elongation is and understand the formula Lf - Lo/Lo I just don't understand where to get the lengths from in the curve, I believe the strain is the elongation of the material but don't know where to get the original an final lengths from. Either from uniform at the 0.2% point or the total elongation.

You need to review the definition of 'engineering strain':

http://www.engineeringtoolbox.com/stress-strain-d_950.html

Scroll down until your reach the section titled 'Strain'.

The elastic modulus is the measure of the elasticity of the material, I know that is measured form 0 to 0.02 ( the 2% rule) of the strain as this is the beginning of the plastic region. As E= stress/strain I thought but it seems that's not the case.

This rule only applies to materials for which there is no region where Hooke's law applies, i.e., the stress is not a linear function of the strain anywhere on the stress-strain curve. Steel, for example, has a well-defined region where the stress-strain curve is linear; aluminum does not, and therefore the 2% rule is used to estimate Young's modulus for aluminum and aluminum alloys.