Numéro
J. Phys. Colloques
Volume 49, Numéro C3, Septembre 1988
DYMAT 88 - 2nd International Conference on Mechanical and Physical Behaviour of Materials under Dynamic Loading
Page(s) C3-253 - C3-260
DOI https://doi.org/10.1051/jphyscol:1988336
DYMAT 88 - 2nd International Conference on Mechanical and Physical Behaviour of Materials under Dynamic Loading

J. Phys. Colloques 49 (1988) C3-253-C3-260

DOI: 10.1051/jphyscol:1988336

MICRO-MECHANISM OF DYNAMIC CRACK PROPAGATION IN BRITTLE MATERIALS

T. SHIOYA1, Y. KOGA1, K. FUJIMOTO2 and R. ISHIDA1

1  Department of Aeronautics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, Japan
2  Department of Mechanical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-machi, Koganei-shi, Tokyo 184, Japan


Résumé
Les micro-mécanismes de la propagation dynamique de fissures est étudié expérimentalement. Un essai de propagation de fissure dans des plaques de PMMA fragile est mis en oeuvre à vitesse constante en utilisant un appareil muni de mors. La surface rompue est observée par microscopie. L'analyse de facies paraboliques sur la surface rompue met en évidence le processus d'initiation des micro-fissures, de leur propagation et de leur coalescence jusqu'à la propagation de la fissure globale. Les conditions de l'initiation des microfissures aux noyaux sont obtenues par examen des facies et par l'analyse des contraintes dynamiques.


Abstract
Micro-mechanism of dynamic crack propagation is experimentally studied. A running crack experiment in brittle PMMA plates is conducted under constant velocity condition by the use of a fixed grip apparatus. The fracture surface is microscopically observed. Analysis of parabolic patterns on the fracture surface shows the process of micro-crack initiations, propagations and their coalescences to the global crack propagation. The condition of the micro-crack initiation at the nuclei is obtained from the examination of the patterns and the dynamic stress analysis.