"Hydraulic turbines can undergo severe damaging during operation, because of low quality water or detrimental flow conditions. Damaging induces maintenance costs and power production losses, and can also endanger safety of installations. Hydropower plants operators and turbine manufacturers are interested in extending overhaul periods by reducing damaging intensity and protecting turbine components with surface treatments. Accurate and reliable prediction of damaging is however missing. The PREDHYMA project aims at developing predictive tools addressing damaging mechanisms and helping engineers to better manage installations’ lifecycle.Four main damaging mechanisms are encountered in hydraulic machines: hydro abrasive erosion, impacts of gravels and stones, cavitation and impacts of water droplets. They result from complex interactions between fluids and solids. The PREDHYMA project aims at predicting these four mechanisms by means of numerical simulations. Current approaches of damaging model micro-scale interactions between fluid and solid. They are not generalist and require calibration often valid on specific configurations only. Besides they do not really account for the shape evolution of turbine components as damaging develops. The PREDHYMA project will overcome these limitations by introducing a multi-scale approach in space and time. Micro scale simulations will compute damaging rate directly from very detailed and local simulations and will feed macro-scale simulations encompassing full turbine components along their operation lifetime.PREDHYMA will deal with diverse and challenging topics in numerical simulations: turbulence, cavitation, fluid-structure coupling, and fracture mechanics, at the frontier between fluid and solid mechanics. The project will also tackle challenges in terms of software engineering and High Performance Computing, providing a unique simulation framework dedicated to damaging prediction in fluid-structure interactions."