The multiscale coupling methods are a powerful tool to study the local phenomenon that occur at the atomic scale. Such methods are generally employed to study for example crack propagations, dislocations or nano indentations. With these approaches, one couples an atomic description which model the material at the finest scale - such as molecular dynamics - with a macroscopic model of continuum mechanics.
The use of a macroscopic model allows to reduce considerably the number of unknowns to handle. Moreover, it is easier to apply force fields or complex boundary conditions to macroscopic models. Thus, this type of coupling can help to provide complex boundary conditions to the molecular dynamics domain.

The LibMultiScale is a C++ parallel framework for the multiscale coupling methods dedicated to material simulations. This framework is designed with the form of a library providing an API which makes it possible to program coupled simulations. At the present time, stable implemented coupling method is based on Bridging Method from T. Belytschko and S. Xiao.

The coupled parts can be provided by existing projects. In such a manner, the API gives C++ templated interfaces to reduce to the maximum the cost of integration taking the form of plugins or alike. Such codes have been integrated to provide a functional prototype of the framework. For example, molecular dynamics software that have been integrated is Stamp (a code of the CEA) and Lammps (Sandia laboratories). The unique software of continuum mechanics, discretized by finite elements, is based on the libMesh framework.

The LibMultiScale is now distributed with a CECILL-C open-source licence. You can visit this page where resides the project.