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Endommagement du verre soumis à des contacts statiques et dynamiques

type de publication      thèse de doctorat
date de publication 09-07-2010
auteur(s) Ismail Jewan
jury Nait Abselaziz M.; Azari Z.; Woznica K.; Rusinek A.; Plufinage G.; Mouwakeh M.; Zairi F.
école Université de Lille 1
  
résumé Glass was and is still a useful material in many applications (buildings, vehicles, aircrafts, electronic, etc). Due to its excessive brittleness, the study of glass behavior submitted to different kinds of loadings (impact/indentation) is a subject of a high interest. In a first part of this thesis, indentation of glass bulk by small-sized rigid spheres was numerically analyzed. An anisotropic continuum damage mechanics (CDM) model was implemented into a finite element program to study the damage pattern in glass. The CDM-based model pointed out three explicit sites for damage initiation. The first was located on the plate surface and considered as the responsible for a cone crack development. The second site, which may produce a median crack, was located on the load axis. The third site, representing the region of permanent deformation, occurred beneath the indenter. The directions of crack propagation predicted by means of the strain energy density factor were found in very good agreement with those experimentally obtained in the literature. The CDM framework used in the static modeling was extended to the dynamic loadings in a second part of this thesis. A particular attention was paid to the cone crack pattern. A simplified CDM-based model (only governed by the maximum principal stress) coupled with the vanishing element technique was employed to follow the cone crack propagation without presuming the initiation site. In the last part of this thesis, the phenomenon of glass erosion was studied from experimental (sandblasting) and numerical approaches. The implemented CDM-based model was used to explain the experimental observations, especially the dependence of material removal on projectile size, impact velocity and impact angle. The experimental work showed an increase in material removal rate by increasing the sandblasting duration and the impact angle. Moreover, a gradient in material removal with respect to the plate center was observed. By modeling various particle sizes and velocities according to those used in the experiments, the numerical simulation of a single impact predicted an amount of material removal in very good agreement with that obtained experimentally. The effects of inter-particle spacing and impact number on the material removal were also pointed out.
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