Evening all, I have a Force vs. Elongation graph of a specimen (Aluminium). From this I need to derive the values of Young's Modulus, Yield Stress, Yield Strain, Ultimate Tensile Strength and so forth. I assumed this was fairly straight forward, but when I tried calculating the UTS, my answer was way way off of what it should roughly be. The calculation I tried is as follows: The maxima of the curve was 53.5kN and the A0 of the specimen was 76.9mm2. UTS = F/A0 = 53500 / 76.9x10-6 = 695.7MPa The answer should be around the 69GPa mark. Any ideas where I'm going wrong? I get similar results when trying to calculate any other values from the graph. Many thanks.