Papers by Author: Fabrice Pierron

Abstract: This paper deals with the use of X-ray tomography and Digital Volume Correlation in order to study the mechanical behaviour of a low density polymeric auxetic foam. First, the metrological performances of the procedure are assessed using rigid body translation. Then, tensile test results are analyzed for two load steps and comments on the deformation process of the foam are given with a specific view to Poisson’s effect.

Abstract: This paper compares the technology and the performances of three ultra high speed cameras for full-field deformation measurements with Digital image correlation or the grid method. The three cameras are based on multiple CCD sensors (Cordin 550-62, with rotating mirror or DRS IMACON 200 with gated intensified CCDs) or dedicated chip (Shimadzu HPV). The advantages and limitations of these cameras are critically reviewed.

Abstract: Tensile tests were performed in order to identify the stiffness components of superconducting windings in the shape of rings (also called ‘double pancakes’). 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, in the orthotropy basis, the four in-plane stiffnesses of the double pancake were determined using the Virtual Fields Method.