ANALYSIS OF THEORETICAL, NUMERICAL AND EXPERIMENTAL DISPLACEMENT FIELDS IN THE BULK OF A CRACKED SPECIMEN.

摘要

The aim of this study is to evaluate 3D numerical simulation and 2D theory on a single edge notch cracked specimen loaded in mode I in light of 3D experimental data. To achieve this aim, Digital Volume Correlation coupled to X-ray micro-computed tomography is used to acquire the three experimental components of displacement through the whole solid. The specimen used for the experiment is made of polyurethane blended with copper particles. Theoretical displacement components are obtained by Williams 2D formulations for both plane-strain and plane-stress approaches. Finally, the numerical simulation is made on the finite element software CASTEM and relies on an existing model based on Nakamura and Parks work with a circular mesh around a straight crack front. A comparison is then performed between experimental, numerical, plane-stress and plane-strain approaches for the full field displacements through the specimen. Theoretical approach provides results different from the ones obtained experimentally, especially for the u_x and u_z components for which theoretical assumptions are not relevant of the experimental reality. Numerical approach gives similar results to the experimental ones; differences between these two approaches are of the same order of the accuracy of the Digital Volume Correlation method.