The MHICA project focuses on the experimental and numerical study of the performances of bilayer armour configurations under multi-hit loading of small- and medium-calibre bullets. Bilayer armours composed of a ceramic plate as front face associated with a ductile backing (made of metal or composite) are nowadays considered as the most performing systems against these threats. Indeed, thanks to their high hardness and compressive strength, ceramics materials favour projectile blunting and/or breakage, thereby limiting the penetration capacity of the bullet. However, few microseconds after impact, the shock wave propagating through the ceramic tile initiates the onset and the growth of numerous oriented microcracks. Thus, most of the dynamic interaction of this type of ballistic event comes down to the penetration of a damaged or broken projectile into an intensively fragmented target. The mechanical behaviour of the fragmented ceramic is supposed to play a major role in the penetration process as well as in case of multiple impacts. This aspect of the behaviour remains largely unexplored and one cannot find in the literature a robust modelling approach based on reliable experimental data. To date, numerical tools are still underutilized in the design process of ceramic-based protective systems. Indeed, it rather relies on empirical approaches with series of ballistic tests. However, considering the numerous parameters to take into account (projectile characteristics, impact velocity, angle of incidence, thickness of constitutive parts …), numerical simulation represents a promising way to optimize the protective systems. Nevertheless, to be predictive, the models implemented in finite element codes have to be reliable, robust and validated by using accurate experimental data. The MHICA project proposes: - to perform instrumented ballistic tests against bilayer armour configurations made with dense or porous silicon carbide front plate, - to study the damage induced in impacted bilayer armour configurations by using CT-tomography analysis, - to develop a new experimental method to characterize the behaviour of fragmented ceramics and to identify a constitutive model to be implemented in a finite element code, - to numerically simulate a single-impact of AP projectiles with both finite-element method and discrete element method, - to numerically simulate a multiple-impact of AP projectiles with the discrete element method taking into account for the initial cracking state provided by the tomographic analysis, - to compare the computational results with the experimental data. Finally the present work should make possible to better understand the relationship between ceramic's microstructure and their dynamic fragmentation on the one hand, and the impact behaviour of the fragmented ceramic one the other hand. The global approach proposed herein, composed of experimental characterization, modelling and numerical simulations, constitutes an innovative way to improve the understanding of the links between material characteristics, mechanisms activated at high strain-rates and performance of an armour system. The works carried out in this project will benefit to the DGA by providing tools to optimize the protective solutions such as body armour of the foot soldiers or the police task forces as well as armour configurations used in vehicles operating on the battlefield

This project between academic and industrial partners bridges the gap between fundamental and applied research. Important aspects of applied research, e.g. availability of the resources, possibility of upscaling and industrialization, long-term performance, will be included from the beginning on into the project. From a scientific point of view, the project studies the impact of microstructure and defects of non-stoichiometric support materials on the catalytic performance. As catalytic reactions, primarily CO and CH4 oxidation will be studied as model reaction for a suprafacial and intrafacial mechanism, involving surface- and lattice oxygen, respectively. In particular, top-down synthesis methods (electric arc fusion + milling) and bottom-up approaches (citrate gel, molten salt, controlled milling and spray pyrolysis) will be used to prepare materials of the (Sr,Ca)(Ti,Fe)O3-x. family. Defects are created during the synthesis (milling, organic additives, Fe-doping in SrTiO3 and CaTiO3). First results show that despite a very low surface area (< 10 m2/g), low temperature catalytic activity can be observed for Pt-impregnated supports of Fe-doped CaTiO3, comparably to standard catalyst support such as ceria. In view of our preliminary results of its catalytic activity, (Sr,Ca)(Ti,Fe)O3-x appears to be a very performant catalyst showing a high potential still to be developed. The impact of different Fe-doping level on the oxygen ion vacancy ordering, oxygen mobility and therefore catalytic performance has, however, not been studied in detail. Here, we want to elucidate the role of the support using detailed structural characterization involving large scale facilities (neutron scattering, operando x-ray absorption spectroscopy) and oxygen isotope exchange reactions (coupled with mass spectrometry, Raman spectroscopy and pulsed reaction). The polar nature of twin boundaries of inherently nonpolar ferroelastic (Sr,Ca)(Ti,Fe)O3-x is supposed to have strong effect on the catalytic performance for oxidation reactions. We therefore aim to explore a panoply of synthesis methods to control and optimize the micro- and domain structure, also in view of short- and long-range oxygen defect ordering. We have already developed novel techniques to better understand catalytic reaction mechanisms, allowing differentiating between surface and bulk oxygen participation and which will be further developed in this project as a standard laboratory technique. This interdisciplinary project involves beside laboratory methods, a variety of cutting-edge characterization techniques only available at Large Scale Facilities. The project links performant analytical catalytic methods and materials properties optimization together with industrial needs, involving new concepts in the synthesis approach of catalytically performant materials, presenting an original synergy approach between solid state reactivity and heterogeneous catalysis.

The present project is dedicated to industrial research for the development of innovative catalytic systems for air purification, such as those used for the control of road vehicle emission (three way converter, TWC). In the context of Europe’s dependency on imports of some critical elements currently used as catalyst support (e.g. cerium oxide), we focus on more available elements such as Ca, Fe, Mn, Sr, Cu… by keeping the well-understood mechanisms governing the catalytic activity of cerium oxide in mind. As such, we choose oxygen ion conductors of the Brownmillerite family as support material, because it has been reported that lattice oxygen atoms have a beneficial impact on the catalytic activity of oxidation reactions. Next to the pure support material, also the interaction of a noble metal with the oxygen ion conductive support for the efficient removal of gas phase pollutants will be studied. In terms of catalytic reactions, the oxidation of CO, and the storage and reduction of NOx will be the primary metrics. In this project, oxygen ion conductors of the Brownmillerite family are chosen as support material. Brownmillerites can be regarded as oxygen-deficient perovskite type oxides. The Brownmillerite type structure is anisotropic with 1D-oxygen vacancy channels providing a catalytically enhanced surface/interface structure. Brownmillerites are known to reveal oxygen ion mobility down to ambient temperature. The presence of extended defects as anti-phase boundaries can significantly decrease the activation energy for oxygen diffusion. Defect-rich CaFeO2.5, which is traditionally known to be a stoichiometric line-phase, can be oxidized under mild conditions to CaFeO3, while the oxidation of ordinary CaFeO2.5 usually requires extreme reaction conditions, i.e. 1100°C and several GPa oxygen partial pressure. Thus, introducing a high concentration of defects seems to be a promising concept to transform even traditionally known stoichiometric line-phases to become a kind of oxygen sponge and behave as oxygen storage/buffer compound at very moderate temperatures. This mechanism is thus comparable to the oxygen storage capacity of doped cerium oxide, and offers a true potential for application in catalysis. Consequently, the Brownmillerite CaFeO2.5 will be a first candidate to study due to its known oxygen ion conductivity properties, however, also doping with other elements (e.g. Cu, Mn, W) and other compositions (e.g. SrFeO2.5) will be investigated. For the support material, we will attempt to achieve (i)- a high degree of dispersion of the noble metal into the matrix, (ii)- a high oxygen mobility at moderate temperatures (e.g. by introducing defects) and (iii)- a high surface area, which we anticipate to be key aspects for achieving high catalytic activity. To date, it is still a challenge to achieve these goals simultaneously for Brownmillerites. As a result, in this project, several synthesis routes are foreseen. More straightforward synthesis routes, such as citrate-EDTA gel methods and spray pyrolysis, will be investigated alongside with more advanced synthetic approaches such and hard-templating routes. This multitude of possibilities allows for an easy adaption of a synthesis route to the material under study. A major part of the project will be dedicated to the detailed characterization of the materials involving large scale facilities for structure analysis and spectroscopy (in-situ studies), including oxygen isotope exchange reactions to trace the oxygen ion mobility. These studies will allow for a detailed understanding of the materials properties in relation to its catalytic activity. The most promising materials will be synthesized on a pilot-scale using electrofusion. This technique is well-established by the industrial partner and is extremely suitable for the synthesis of reduced powders, such as CaFeO2.5.

Granular matter and powders are widely used in the manufacturing of numerous products and in many industries. Despite this intense utilisation, their behaviour and rheological properties are still badly understood. One major difficulty is that powders and their ability to flow are strongly affected by cohesive effects. In worst cases, the flow may stop and is somehow difficult to start again. A concept of “flowability” has been introduced through different qualitative indexes to characterize the ability of powder to flow, but the flowability is not clearly related to physical and rheological properties of the powder. As a result, characterization tools available for the companies working with powders provide disparate measurements and only give qualitative information about the flow properties. Our objectives in this COPRINT proposal is twofold: 1) providing a physical understanding of the concept of flowability by studying the rheology of powders in various configurations both experimentally and numerically. 2) designing innovative tools to characterize powders for the industrial partner. The first goal will be achieved by coupling experiments on a controlled-cohesive granular material as well as on real industrial powders with numerical simulations both discrete and based on continuum modelling. In the same spirit as what has been developed the last 15 years to study dry granular materials, our study will focus on simple but physically relevant configurations like inclined planes, shear cells, rotating drums. A central question we would like to focus on, will be the response of the powder to transient flows and to perturbations, to test if the flowability concept might be related to clogging instability. The second aim of the project is to use our better knowledge of the rheology to design new tools to characterize powders in industrial environments. The design of these new tools should be simple enough to be implemented in severe industrial conditions but should also provide quantitative measurements directed related to the rheological properties of the material. Three configurations have been identified as potentially relevant: inclined plane, flow around a cylinder and rotating drums. This ambitious project of both academic and industrial interest is proposed by a consortium of 3 partners, two complementary academic laboratories (IUSTI and ?’Alembert) and an industrial partner (CREE Saint Gobain) and will take place on a long-term program of 4-years. It will gather scientific, academic and industrial skills and should extend the recent progresses on the rheology of granular matter to cohesive powders and provide new tools for an industrial usage.

This project is focused on thermoelectric materials with potential industrial applications at very high temperature, from 600°C to 1000°C and possibly higher, to harvest waste heat and convert it into usable energy. This particular temperature range targets the steel, non-ferrous, ceramics and glass industries that use a lot of energy, 50% of which being lost during the production process. this project will target the research and development of high temperature stable thermoelectric materials based on the cubic structure Th3P4. In this family of intermetallics, n-type La3Te4-x are already known as good thermoelectric materials with ZT above the unity above 1000°C. This project therefore proposes to develop a p-type counterpart of the same structure type, e.g rare-earth antimonides crystallizing in the anti-Th3P4 structure, making it easier to fabricate p-n thermoelectric couples. However, there is only scarce information about the p-type counterparts, even if a few reports have shown very promising thermoelectric properties and stability at high temperature, for instance a ZT of 0.75 was reported in La0.5Yb3.5Sb3 at 1000°C. These materials, their optimization (using modeling tools) and their implementation within a thermoelectric uni-couple and the subsequent demonstrator tests and qualifications are the focus of this proposal. The materials will be made via mechanical alloying followed by annealing and spark plasma sintering. These particular techniques have already proven that they allow the control of whole process, thus assuring the reproducibility of the obtained thermoelectric properties. With the development of powerful methods to compute the electronic band structure of solids and the increasing complexity of the formulations of advanced thermoelectric materials such as those targeted in this project, quantum chemical calculations based on density functional theory (DFT) will be used for the optimization of thermoelectric material properties. DFT programs embedding the most advanced approximation of the exchange-correlation functionals and taking into account relativistic effects will be employed to calculate the electronic structures required to use band engineering approach for the optimization of the thermoelectric properties of the studied materials. The third step of the project will focus on the making of the TE legs, namely, the active materials contacted on both side by metallic electrodes. This will be achieved using the LINK facilities and equipment and will be fed by the data available on the n type material (La4Te3-x) developed by NASA-JPL. CRISMAT will participate in the making of the metallized legs, metallographic studies will be performed on the different bondings and transport properties will be monitored upon ageing of the assemblies. Finally, the last challenge will be to actually build a thermoelectric converter. In essence, it consists of several unicouples connected electrically in series to form a module. The power delivered by such device obviously depends on the number of unicouples. In order to keep the project realistic and in order to be able to respond quickly to necessary design modification, small demonstrators will be privileged over large units. Besides characterization of the TE modules, these tests would serve to anticipate the applicability of the modules in industrial conditions, and anticipate potential modifications to the original design. The efficiency and durability of the module, will be used to estimate how much energy can be recovered and the economic advantage for an industrial application. Data will serve to identify other potential application domains for the modules, according to industrial process characteristics. The consortium ideally combines the expertise of well know research center, CRISMAT laboratory, IRSN Rennes, NIMS Tsukuba via the UMI LINK, and an end user: St Gobain via the CREE research center and also via its belonging to the LINK UMI