Calculated Young's Modulus smaller than typical value (steel)?

[MegaDeth]

Homework Statement

I carried out an experiment using a extensometer, had a range of values for the elongation and load. I calculated the value from the data and had 11GPa whereas it should be 200GPa. Do you know what could have gone wrong? Thanks a lot.

 

[PhanthomJay]

Homework Statement

I carried out an experiment using a extensometer, had a range of values for the elongation and load. I calculated the value from the data and had 11GPa whereas it should be 200GPa. Do you know what could have gone wrong? Thanks a lot.

Are you sure you plotted stress (in GPa) versus strain (dimensionless)? If you are looking for Youngs Modulus, you need to look at the initial slope of the graph you plot (i.e, tangent to curve at low stress value, although for steel the curve should be close to linear below the yield stress).