Hi, I have a solid cylinder to which I have strain gauges attached to measure axial and circumferential strains. My goal is to relate the circumferential strain to radial strain and then to calculate possion's ratio. Every time I try to work out the geometry of the problem I end up saying that circumferential strain is equal to axial strain, can this be true? Terms: Ec = Circumferential Strain = dC/C dC = change in length of circumference C = circumference Er = Radial Strain = dR/R dR = change in length of radius R = radius Here is my logic: Strain Circumferential (Ec) is equal to the strain is see in one single strain gauge attached along circumference. dC = 2*PI*dR. Then dR can be expressed as dR = C*Ec/(2*PI). Which means Er= dR/R = C*Ec/(2*PI*R) = Ec. Can that be right? Then is my possion's ratio radial/axial or axial/radial? Thanks.