The demanding service environment associated with nuclear energy systems require materials tailored for high performance under high mechanical loading, temperature and irradiation, which slowly modifies their microstructure, thus their mechanical behavior. Understanding this evolution through numerical modeling is therefore an important task.

Dislocation dynamics simulations are designed to model the material behavior at the microscopic scale, by explicitly accounting for the interactions between the dislocations, the microstructure and radiation-induced defects. CEA, CNRS and INRIA have been teaming over the last decade to develop the simulation code NUMODIS, which relies on a hybrid MPI/OpenMP approach. The goal of this thesis is to design and implement new algorithms, and ultimately allow for simulations over hundreds of thousands or cores on heterogeneous platforms.

Special attention will be dedicated to long-range elastic calculations through the hierarchical multipole method, extending the latter to anisotropic elasticity, generalized crystalline defects, displacement field calculation and periodic boundary conditions. Newly proposed time-integration (sub-cycling) algorithms will also be explored in combination with advanced asynchronous collision handling algorithms.

A team combining physicists and high-performance computing specialists will supervise this work.