Identification of the Mechanical Properties of Superconducting Windings Using the Virtual Fields Method

Tensile tests were performed in order to identify the stiffness components of superconducting coils. The stereo image correlation technique was used for full-field displacement measurements. The strain components were then obtained from the measured displacement fields by numerical differentiation. Because differentiation is very sensitive to spatial noise, the displacement maps were fitted by polynomials before differentiation using a linear least-square method. Then, the four in-plane stiffnesses of the double pancake were determined using the Virtual Fields Method in the orthotropy basis.