How to convert force displacement curve to stress strain curve

[fishfried]

Hi
i need help with this conversion as i am unsure how to approach this.
I have obtained a force vs displacement curve from a Hounsfield materials testing machine, and would like to know how to convert this to a stress vs strain curve.
Thanks

 

[KLoux]

How are stress and strain define? (show us some equations)

This is a pretty simple problem, and I think if you look at the equations, you will be a lot closer to understanding what you need to do.

-Kerry