This paper presents a new computational method and the associated software dedicated to the study of the dynamic fracture of nonlinear and heterogeneous materials. This method is based on the concept of Frictional Cohesive Zone Model in the framework of Non-Smooth Contact Dynamics. The associated numerical platform, composed of three object-oriented libraries, allows to simulate, in three dimensional finite deformations, the dynamic fracture of both multiphase and functionally graded materials from crack initiation to post-fracture behavior. The ability of this software, developed by the French ’Institut de Radioprotection et de Sûreté Nucléaire’ (IRSN) in the frame of its research program on nuclear fuel safety, is illustrated on the fracture of hydrided Zircaloy-4, constituting nuclear cladding tubes at high burnup, during a reactivity initiated accident (RIA). The macroscopic behavior of this heterogeneous material is deduced as an averaged energy release rate depending on the volume fraction of hydride phase.

Nous présentons dans ce papier une nouvelle approche pour l’étude de la fissuration dynamique de matériauxhétérogènes. Cette approche est basée sur la notion de Zone Cohésive et sur la méthode Non-Smooth Contact Dynamics.La plateforme numérique associée (conception orientée objet) permet des simulations tridimensionnellesen grandes déformations de la fissuration dynamique de matériaux multiphasiques ou à gradient de propriétés,depuis l’initiation de la fissuration jusqu’à la ruine du matériau. Un exemple de fissuration de composite à matricemétallique de l’industrie nucléaire, le Zircaloy-4 hydruré, est présenté.

Ce papier présente un outil de simulation numérique permettant l'étude de la fissuration dynamique des matériaux hétérogènes et à gradients de propriétés. Cet outil est basé sur la notion de Modèles de Zone Cohésive Frottante et sur l'approche Non-Smooth Contact Dynamics. La plateforme numérique, composée de trois librairies avec une conception orientée objet, permet des simulations tridimensionnelles en grandes déformations depuis l'amorçage des fissures jusqu'à la ruine finale du matériau. Un exemple de fissuration de matériau hétéro-gène utilisé dans l'industrie nucléaire, le Zircaloy-4 hydruré, est présenté.

A new numerical strategy, based on the coupling between the Cohesive Zone Model (CZM) concept and the Non-Smooth Contact Dynamics (NSCD) approach, for the simulation of the dynamical fracture of heterogeneous materials is presented. The associated software, composed of three libraries with Object Oriented Progam-ming, allows to simulate, in 3D and large deformation, the dynamical fracture of non linear and heterogeneous materials from fracture initiation to post-fracture. The ability of the software, developped by the French "Institut de Radioprotection et de Sûreté Nucléaire" (IRSN) in the frame of its research program on Nuclear Reactor Fuel Safety, is illustrated on the fracture of an heterogeneous material-1 the hydrided Zircaloy-4 constituting standard nuclear cladding tubes-submitted to transient loading.

In order to account for the faceted shapes of ballast grains, we use pentagonal grains in a two-dimensional space. The grains are confined inside a rectangular box with thickness H and length L. The two side walls are free to move horizontally, the base is fixed, and the top wall is subjected to a compressive load or displacement. The numerical sample is composed of approximately 1600 grains: 50% of diameter equal to 2.5 cm, 34% of diameter equal to 3.75 cm, 16% of diameter equal to 5 cm. The coefficient of friction between the grains is µg = 0.6. We used a coefficient of friction µw equal to 0 or 0.6 between the grains and the top and bottom walls.

To understand the complexity of dense granular flows, we used three-dimensional (3D) numerical simulations which appears as complementary approaches to the experimental ones. Numerical simulations allow (i) to investigate the influence of parameters difficult to control experimentally and (ii) to measure quantities inacessible to experiments. In this paper we focus on numerical 3D rotating drums and shed light on the role of lateral friction on the rheology of dense granular systems. Our framework is the Non Smooth Contact Dynamics approach, powerful to perform accurate simulations of large systems of particles, essential to deal with simultaneous contacts. We point out the influence of lateral friction coefficient on the granular flow and compare the results to previous 2D simulations.