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

IRIS is an object oriented, general purpose, simulaiton code for conducting research in solid, fluid, and structural mechanics. The 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 is written in C++, and employs optimised external libraries for the heaviest tasks, like linear equation solving, meshing, domain decomposition, etc.

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

  • Solid mechanics: Linear and nonlinear analyses, standard, mixed, and stabilized formulations for linear and nonlinear analyses. Modal computations.
  • 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. Incompressible and compressible flows.
  • Time-Integration algorithms: Implicit and explicit methods for structural dynamics (Newmark, HHT, G-alpha, midpoint, Euler), structure preserving methods (Energy-Momentum, Energy-Entropy-Momentum)
  • 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.