My fault, I’m used to pulling stress strain off of an Instron. I need to learn to read the axis on a graph😳. I thought you used a constant minimum cross section and calculated stress. Didn’t notice till after the post.
Granted you aren’t dealing with a material that has a typical stress strain curve, it has elastic properties, a non constant cross section, technically it’s a composite… so I agree the comparison to a standard material is a stretch(pun intended,) and likely the very reason you had to force a linear fit. So I suppose it would be more out of pure curiosity than anything else. You’re right though, stress/strain vs. force/strain would look identical, as you would have approximately the same minimum cross section for all samples. Only thing you would get by switching axis and expressing it as mm/mm instead of % is the same thing @gmac has, so no point. 