In line with the Key Strategic Orientation (KSC) C of the Strategic Plan “Making Europe the first digitally led circular, climate-neutral and sustainable economy through the transformation of its mobility, energy, construction and production systems” and with the Circular Economy Action Plan “For a cleaner and more competitive Europe”, the proposal “TURBISURF” intends to produce new and repaired complex surfaces of hot section turbine components using digitised, environmentally friendly, energy and chemical-lean processes. Self-monitored electrochemical processes will allow to selectively strip oxide and corrosion products and worn coatings without affecting the expensive substrates. The digitisation will target local areas or the full complex external and internal surfaces. Each component will be processed individually within the same batch allowing full customisation of the process. The same principle will be applied to electropolish the local or the whole surfaces dimensionally restored by additive manufacturing allowing to tailor the roughness of the surfaces. After cleaning and restoring or directly applied onto new components, slurry coatings with and without Ni and/or Pt electroless sublayers will be deposited on digitised surfaces with 3D computed movement/rotation. Destructive and Non Destructive Testing (NDT) will allow to estimate the lifetime of the new coated and repaired complex surfaces vs. the state of the art. The shared results onto different components will contribute to standardise the digitised processes developed in TURBISURF. The Lifecycle analysis (LCA) will assess the economic and ecologic contribution of the approaches to circular economy with a view of real exploitation in European SMEs and large companies. The Academic and Industrial consortium will develop the skills of young European scientists, engineers and economists on the advanced digitalised processes developed here. Overall, a digital transformation of the processes will ensure that the Destination “Climate neutral, circular and digitised production” is successfully reached after 4 years of involvement and that other business sectors (e.g. automotive) can benefit from TURBISURF.

One of the elementary physical mechanisms implied at the first stage of corrosion fatigue processes in presence of hydrogen in nickel is investigated during the CRACKHINIT project. Here, we focus on the hydrogen embrittlement phenomenon during fatigue, which has many implications for the durability of metallic structures in the industry and for the sustainable development societal field. The investigated processes are related to the hydrogen-vacancy-surface interactions under stress, which remain unclear. In particular, these interactions can deeply affect the solubility and the diffusion of the solute, but also the formation and the mobility of the vacancies during fatigue through the formation of slip bands at the surface. The study implements both a theoretical approach based on atomic scale calculations conducted within DFT and an experimental part performed on single crystals with cyclic deformation tests under an in situ hydrogen flux or on ex situ H charged materials. Here, the chosen material is fcc nickel for its common applications in the industry and it is widely studied in our laboratory. The surface and the subsurface layers of the material after fatigue tests are characterized in terms of density of defects and roughness (i.e, the height of the slip band at the surface). The vacancy and hydrogen concentrations and the diffusion coefficients of the particles are determined for several deformation states and/or hydrogen fluxes in the subsurface layers within calorimetric and electrochemical techniques. The atomic scale calculations are conducted at finite temperature on supercells based on the lattice repetition of the conventional Ni fcc structure to investigate the energetics of H and vacancy concentrations and diffusion on the (100), (110) and (111) surfaces and on their subsurface layers. The temperature is taken into account from the calculations of the free energy from a sum of vibration and electronic excitations contributions. Additional calculations are conducted to take into account the effects of a stress state and the formation of steps at the surface, which represent the first stage of the emergence of the slip bands. The comparison between the experiments and the DFT calculations put in forward the most influent parameter (surface state, stress state, height of the slip band) affecting the H diffusion and solubility but also the formation and mobility of vacancies during fatigue. The expected results can be used to develop new macroscopic models and to define criteria on the initiation of cracks and damage in situations of corrosion – fatigue in presence of hydrogen. These models and criteria help to define new metallurgical states tolerant to H embrittlement and can be transferred to the industry in the future.

Energy flexible buildings can support the integration of renewable energy sources in the national energy mix by modulating their energy use. Modulating the heating energy use of new and existing buildings could provide 10 to 20 GW of flexible load in France according to the literature and demonstrator projects. Despite a large potential identified, a number of issues prevents the deployment of this technology: communication, privacy, cost-effectiveness, control and reliability of the response. This project focusses on the last two issues and will test indirect control strategies to maximise the flexibility potential and coordinate the response of energy flexible buildings. The advantages of indirect over direct control strategies are the ease of deployment and the respect of the users’ privacy. The use of an indirect controller will ensure that the objective of matching production and demand is achieved at the aggregated level, though allowing some degrees of freedom at the building scale (the signal sent can be interpreted differently by each end-user’s energy management system). However, the main challenge of indirect controller is to get a reliable estimation of the capacity available, in order to be able to trade the capacity on the electricity market. This lack of reliability in the response has been identified as a barrier to the development of indirect control strategies for demand response. In this project, indirect control strategies combined with a rule-based controller (RBC) at the building level will be simulated on different case studies, accounting for the diversity of buildings and users. This project is centred on the building energy use, but will consider the problem from a district perspective using an integrated and multidisciplinary modelling approach, in order to come up with robust and optimised solutions. The project is coordinated by LaSIE (La Rochelle), and partners from G2Elab (Grenoble) will bring their expertise in the modelling of electrical networks. The project is divided in three main parts: the first part is related to the development of the simulation platform, the second part to the evaluation of the control strategy on the Atlantech low carbon district, and the last part to the robustness and of the reliability of the controller developed. In the first part, the building models will be defined using building energy simulation tools and grey-box models will be developed to ensure a short computation time. The building typology of the Atlantech low carbon district will be used as a reference and different types of users (based on stochastic modelling) will be considered. In parallel, the LV electrical network and the local production systems will be developed. Steady-state and simple modelling techniques will be used to focus on the main problems that can arise from energy flexible buildings (e.g. peak demand, ramping, voltage stability). The last step of the platform development will be to validate the integrated model using measured data from the Atlantech district in La Rochelle. Based on this integrated model developed, indirect control strategies combined with RBC will be tested and analysed on the case-study to properly evaluate the performance at the grid and building levels. The objective of this part is to check that the proposed control strategy makes use of the flexibility potential and does not create any side-effects. Finally, the last part will focus on the reliability of the control proposed and will extend the work to more case-studies. The sensitivity of the controller will then be evaluated, by varying the response of the users, the types of building and the environment. The results of the project can be used to define control strategies that enable demand response for residential customers and also to provide tools for a reliable estimation of the shifting capacity under indirect control.

This work aims to evaluate the impact of plasticity and the nature of grain boundaries on hydrogen-induced brittle fracture mechanisms in nickel base alloys. In this context, and using innovative multiscale numerical and experimental approaches, we will interrogate in the presence of hydrogen, the implication of the mechanisms of plasticity coupled with the nature of the grain boundaries on the processes leading to the decrease of mechanical properties of metallic materials. The purpose of the project is the establishment of a damage map associating the modes of fracture, the character of the grain boundaries and the hydrogen-plasticity interactions.

The shape and mass optimization can make the submerged structures, for instance hull appendages of ships and components of marine renewable energy systems, particularly sensitive to external loads. This sensitivity influences several properties, including wear, fatigue and stealthiness. The related economic issues (definition of refined design margins and reduction of damage probabilities or acoustic discomfort) are of paramount importance for the entire shipbuilding industry, both civil and military. The crucial point for a reliable design in these domains lies in a relevant assessment of each parameter influence: intensity and direction of current, characteristics of materials and mechanical loads. In industry, the design of structures is evaluated by capitalizing on a very limited number of configurations and scenarios, mainly derived from the intuition and practice of designers. For optimized structures or new concepts, by definition without any feedback, the risk of under-sizing is recognized. An appropriate design requires knowledge of relevant parameters and the impact of their variabilities. This information may be obtained for example via the resolution of numerous numerical simulations, by varying the parameter values. In industrial applications, this cannot be achieved with high-fidelity models, that require prohibitive CPU time. This is an important technological barrier, which can potentially be raised by the development and use of parametric reduced order models (ROM), if they combine speed, accuracy and reliability. The aim of the project MODUL'O PI is to develop such models, adapted to the underlying difficulties (high Reynolds numbers flows; complex submerged structures), and to foster the transfer to industrial applications, specially for wear, fatigue and acoustic stealthiness. Two main problems shall be solved to reach this objective: (P1) the influence on the hydrodynamic load of uncertainties related to the flow configurations; (P2) the influence on the vibratory level of uncertainties related to the loads and materials parameters. To tackle these issues, this project is divided into three tasks. Obtaining a reduced parametric formulation of the hydrodynamic wall pressure, problem (P1), will be the subject of tasks 1 and 2. A meta-model of the wall pressure will be built in task 1, with an approximation obtained through non-intrusive sampling approaches: statistical learning techniques and use of multi-fidelity models. In task 2, the ROM will be obtained through Galerkin methods and the variations of the parameters will be tackled by interpolation on Grassmannian manifold and enrichment via low rank approximation algorithms. The problem (P2), more applied by nature and oriented submerged structures dynamics, will be the subject of task 3. The technical difficulty comes from the high dimensionality of the parameter space: the reduced basis of the related ROM will be built iteratively with a low number of calls to the full model, thanks to a dedicated greedy algorithm and an efficient a posteriori error estimator. In the long run, the use of reduced-order models may be considered in the design phase of a ship or marine renewable energy installation. From the industrial standpoint, taking into account the parametric variabilities will ensure increased control of design margins and lead to longer life time and reliability of marine structures. The technical and economic benefits concern the reduction of manufacturing cost and those related to operational maintenance, ensuring the competitiveness of shipbuilders and the profitability of marine renewable energy installations.