Getting stress-strain data using the 'strain hardening exponent'.

[MarkH748]

Hi guys,

I am trying to generate tabular stress-strain data from the data given in this table for a grade of aluminium,

The elastic region is simple but I don't understand how to use the 'strain hardening exponent' to generate stress-strain data for the plastic region. From what I understand it should follow this equation,

σ = Kεⁿ

where n is the strain hardening exponent
and K is the strength coefficient which is defined as " the extrapolated value of true stress at a true strain of 1.00."

Should I not have been given this value of K in order to plot the data or is there another way to generate the data based on the information given in that table?

Any help would be greatly appreciated!

Mark

 

[Achy47]

Hi Mark,

Great question! The strain hardening exponent is a key factor in understanding the plastic behavior of a material. It represents the rate at which the material becomes stronger as it is deformed. In order to generate stress-strain data for the plastic region, you will need to use the equation you mentioned: σ = Kεn. However, you are correct in that you will need to know the value of K in order to plot the data.

Fortunately, there are a few ways you can obtain the value of K. One way is to use the yield strength of the material, which is typically given in the table you provided. The yield strength is the stress at which the material begins to deform plastically. You can use this value to solve for K using the following equation:

K = σy/εy^n

Where σy is the yield strength and εy is the corresponding strain at the yield point. This will give you the value of K for that specific material.

Another way to obtain the value of K is to perform a tensile test on the material and directly measure the strength at a strain of 1.00. This will give you the true value of K for that specific sample.

I hope this helps! Let me know if you have any other questions. Good luck with your data generation!