During the CACHMAP project, experimental and data processing methods have been developed. The phenomena were identified in the measurements obtained. After having demonstrated the principle of cavitation phenomena, the present project proposes to proceed to the next step which consists in proposing an assembly for the purpose of ballistic protection, much more lighter. The consortium wishes to deal with the case of transparent ballistic protections involving the civilian and military world in multi-impact: personal protections of the combatant, protections for vehicles, protection of infrastructures etc. The various technological bricks from fluids to microstructures would be integrated into a set that makes it possible to perform representative ballistic tests. The objective of the project is to obtain a ballistic plate including the concept of transparent cavitating armor offering a reduction of at least 20% compared to a solution against the threats of Level 1 and 2 of the STANAG 4569 or level EN 166-A for personal protection masks and visors (stop of a steel ball of 6mm diameter and 0.86g mass launched at 190m.s-1). The targeted applications are: - The transparent protections of the fighter to counter ballistic threats of 9 mm or fragments. These protections are currently in PMMA or Polycarbonate. The introduction of a fluid phase in a transparent assembly would reduce the weight of the protection by 20% given that PMMA is 20% heavier than water. - Protections for vehicles (windows) against 7.62 API BZ threats at level 1 and 2 at first.

In turbojet aircraft engines, reducing fuel consumption and specific emissions of CO2 and NOx need to control the clearance between rotor and stator and consequently to master the blade-casing interactions. These interactions are strongly conditioned by the choice of the coating inside the casing. With regard to braking systems, regulations intend to reduce environmental impacts (noise, particulate emissions) and to increase performance of energy dissipation (high speeds). These specifications need to master the phenomena of friction and the choice of materials in contact. The solutions implemented by manufacturers are based on the use of feedback based approaches and "trial and error" that led to the development of "recipes of heterogeneous materials” performance, with regard to brake lining and turbojet casing coating. However, in the absence of a real understanding of phenomena, such "black box" approaches are facing the new technical and environmental requirements. Besides it generates high development costs due to the number of trials needed. The project objective is to develop a methodology to design multi-scale friction materials. This methodology fills in the missing link within the process of understanding and modelling systems (brakes and rotor-stator assemblies for jet engines) in order to increase their energy efficiency and to reduce environmental pollution (noise, pollution...) while maintaining reliability as part safe. Due to high complexity, the approach relies on the one hand on the identification of physical dominating phenomena and, on the other hand, on an experimental-numerical dialogue. Manufacturers (Snecma, FBF-Bosch and FTG-Faiveley) and some academic teams already have an extensive experience with the targeted applications and knowledge of the physical phenomena involved (LaMCoS and LML-ER5). They propose to add skills of other research teams on multi-scale approaches (IJLRDA and LML-ER4) and in the physical chemistry of surfaces (KUL). The approach is based on the following key points: - Definition of "model materials" representative of industrial material formulations reduced and controlled, which will be characterized in terms of heterogeneities and properties. - Approved friction tests with quantitative characterization of material properties and interface (third body) and their gradients. Innovative ways to rheological characterization will be implemented (rheometers and meso-tribometers). - Multi-scale multi-physics numerical innovative approach considering the heterogeneity of materials and interface. This will be done through multi-scale numerical and semi-analytical homogenization. The main benefits are to achieve: A methodology to "design" friction materials for brake applications and casing coatings for turbojet engine. A multi-scale modelling of material - contact interface, integrated into the industrial methodology for analysing performance of brake systems and aeronautic engines. From a scientific perspective, the major benefit is a "homogenization tribological interpretation" that will be a first in tribology.