Three dimensional image correlation from X-Ray computed tomography of solid foam

This work is part of a project (PHOTOFIT) funded by the Agence Nationale de la Recherche. We acknowledge the European Synchrotron Radiation Facility for provision of synchrotron radiation facilities and we would like to thank Joanna Hoszowska for assistance in using beamline BM05.A new methodology is proposed to estimate 3D displacement fields from pairs of images obtained from X-Ray Computed Micro Tomography (XCMT). Contrary to local approaches, a global approach is followed herein that evaluates continuous displacement fields. Although any displacement basis could be considered, the procedure is specialized to finite element shape functions. The method is illustrated with the analysis of a compression test on a polypropylene solid foam (independently studied in a companion paper). A good stability of the measured displacement field is obtained for cubic element sizes ranging from 16 voxels to 6 voxels