The impact of a projectile on a granular material induces important changes in the micromechanical properties of the impacted material. These changes are studied using a Discrete Element Method model of the impact. The numerical results show that the impact first entails an energy propagation from the impact point to the limit of the sample through the existing force chains. A significant kinetic energy and a total breakage of the existing contact force chains are the main consequences of the energy propagation. During the long recovery balance phase observed after the energy propagation phase, frictional processes cause the kinetic energy dissipation. The motions of the particles and the numerous contact openings first prevent the formation of stable force chains. However, for long durations after the beginning of the impact, contact openings stop. The balance recovery phase therefore finally results in the creation of new stable contact force networks.
L'impact d'un projectile sur un matériau granulaire entraîne d'importants changements des propriétés micro-mécaniques du matériau impacté. Ces changements sont étudiés à l'aide d'un modèle d'impact basé sur la Méthode des Eléments Discrets. Les simulations mettent en évidence que l'impact conduit tout d'abord à une propagation d'énergie du point d'impact vers les limites de l'échantillon impacté le long des chaînes de forces existantes. Cette propagation d'énergie conduit à la destruction des réseaux de forces existants et à l'augmentation significative de l'énergie cinétique en tout point de l'échantillon. Durant la longue phase de retour à l'équilibre suivant la propagation d'énergie, l'énergie cinétique est dissipée par frottement. Les mouvements des particules et les nombreuses ouvertures de contacts empêchent tout d'abord la formation de chaînes de forces stables. Dans un second temps, les ouvertures de contact cessent, ce qui permet la formation de nouveaux réseaux de forces stables et, par conséquent, le retour à l'équilibre de l'échantillon.
Mots-clés : Milieux granulaires, Impact, Méthode des Eléments Discrets, Réseaux de forces
Franck Bourrier 1; François Nicot 1; Felix Darve 2
@article{CRMECA_2010__338_10-11_639_0, author = {Franck Bourrier and Fran\c{c}ois Nicot and Felix Darve}, title = {Evolution of the micromechanical properties of impacted granular materials}, journal = {Comptes Rendus. M\'ecanique}, pages = {639--647}, publisher = {Elsevier}, volume = {338}, number = {10-11}, year = {2010}, doi = {10.1016/j.crme.2010.09.007}, language = {en}, }
TY - JOUR AU - Franck Bourrier AU - François Nicot AU - Felix Darve TI - Evolution of the micromechanical properties of impacted granular materials JO - Comptes Rendus. Mécanique PY - 2010 SP - 639 EP - 647 VL - 338 IS - 10-11 PB - Elsevier DO - 10.1016/j.crme.2010.09.007 LA - en ID - CRMECA_2010__338_10-11_639_0 ER -
Franck Bourrier; François Nicot; Felix Darve. Evolution of the micromechanical properties of impacted granular materials. Comptes Rendus. Mécanique, Micromechanics of granular materials, Volume 338 (2010) no. 10-11, pp. 639-647. doi : 10.1016/j.crme.2010.09.007. https://comptes-rendus.academie-sciences.fr/mecanique/articles/10.1016/j.crme.2010.09.007/
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