The main tool for the research in our group is iris, a simulation code developed entirely within our group in the last ten years.

Iris is an object oriented, general purpose, finite element code for conducting research in solid, fluid, and structural mechanics. It has been fully programmed in our group during the last decade. Design considerations for the code have been:

  • Very flexible data structures
  • Readable code
  • Fast
  • Multiple modes of operation: single computer mode (multi-threaded for high performance on multi-core processors), and multi-computer mode for clusters and supercomputers (with MPI).

The code has been in constant evolution for the last years, and now it possesses, among others, the following capabilities:

  • Solid mechanics: Linear and nonlinear analysis, standard, mixed, and stabilized formulations for linear and nonlinear analyses, small and finite strain elastic, viscoelastic, elastoplastic and visco-elastoplastic materials, eigenvalue analysis.
  • Structural mechanics: geometrically exact bars, membranes, beams and shells, homogeneous and composite sections, NURBS generated surfaces
  • Fluid mechanics: stabilized Stokes and Navier-Stokes stationary and transient equations, Eulerian and Lagrangian discretizations
  • Time-Integration algorithms: Implicit and explicit methods for structural dynamics, structure preserving methods
  • Other libraries: manipulation of vectors, matrices and sparse matrices, output to gmsh and paraview


All the material models of iris are now part of muesli, a Material UnivErSal Library. This library includes the constitutive response of many linear and nonlinear, small and finite strain materials. It is programmed in C++ and has interfaces to commonly used commercial codes.

Muesli is open source, and is distributed under GPL3 license.