From Modelica models to dependability analysis

Modelica is a modeling language which was created in order to ease the description of multi physics systems thanks to an object oriented approach. Modelica models usually represent only the nominal functioning of systems and are used to simulate them for design purposes. This article proposes various ways to derive dependability models from such Modelica models, as automatically as possible. Depending on the tightness of coupling between the continuous processes and discrete events such as failures and repairs, the methods proposed here range from the addition of stochastic behavior in the Modelica model itself to the association of the system structure to a library written in the Figaro reliability modeling language. Such an association allows the use of the Figaro workbench tools, specially designed for dependability analysis; it is then possible to generate a fault tree, or to create automatically a discrete stochastic simulation model. All these possibilities are exemplified through two classical use cases: a telecommunication network, and a "heated tank" system.