Finite Deformation Tensor in Cylindrical Coordinates

Hi, I have been looking at non-linear Elasticity. The components of the finite deformation tensor is defined as F_i_j = partialDiff(x_i)/partialDiff(X_i) with i & j = (1,2,3) With x being the position vector in the deformed state and X the position vector in the undeformed state. I am having troubles with this when using Cylindrical Coordinates. When calculating the components for the torsion and extension of a circular cylinder, i cannot get the correct answer. If any body could run me through calculating the components of this tensor in Cylindrical coordinates i'd very much appreciate it. Cheers Richard

Did you remember to multiply by the Jacobian of the coordinate change?