FE2TI

CDS members associated with the software: Prof. Dr. Axel Klawonn, Dr. Martin Lanser

The software package FE2TI is a combination of the FE2 method with hybrid domain decomposition/multigrid solvers and is currently used in the field of solid mechanics for materials with a fine microstructure, as, e.g., dual-phase steels. The FE2 method is a computational micro-macro scale bridging approach directly incorporating micromechanics in macroscopic simulations. In this approach, a microscopic boundary value problem based on the definition of a representative volume element (RVE) is solved at each macroscopic Gauß integration point. Then, volumetric averages of microscopic stress distributions are returned to the macroscopic level, which replaces a phenomenological material law at the macro scale. The microscopic problems are thus coupled through the macroscopic problem. On the RVEs nonlinear implicit solid mechanics problems have to be solved. The MPI and OpenMP parallel software is implemented in C/C++ using PETSc, MUMPS, Pardiso, and hypre. FE2TI is extremely scalable up to millions of MPI ranks and is member of the High-Q club since 2015. In the High-Q club, codes are listed which have scaled efficiently to the complete JUQUEEN supercomputer at FZ Jülich.

In FE2TI, each RVE is assigned to its own MPI communicator and thus the microscopic computations scale nearly perfectly. Apart from that, several features are included in FE2TI: different microscopic solvers, as, e.g., highly scalable (nonlinear) FETI-DP, (nonlinear) BDDC, and AMG approaches as well as robust direct solvers, an iterative approach using AMG for the macroscopic problem, unstructured as well as voxel meshes for the RVEs, and hyperelastic as well as elasto-plastic material models. Recently, a contact formulation has been added to the macroscopic level and complex contact problems can now be handled by the FE2TI package. The FE2TI code is developed jointly with the group of Prof. Dr. Oliver Rheinbach, TU Bergakademie Freiberg.