Most hydraulic, thermal and energy (turbine, pump, turbo-jet engine, ...) used in many sectors (transport, energy, ...) are composed of mechanical sub-assemblies, some of which are particularly sought. These systems will experience during their term of service appeals to maintenance or suffer damage. The objectives of this module are so focused on the analysis of the limiting phenomena of life (seed and crack for example) of these systems for which it is to anticipate the interventions on critical parts. These objectives also have many applications in the steps of sizing systems and equipment in connection with their technical specifications if these phenomena are integrated upstream studies.