Analyse fréquentielle de l'usinage des composites

le perçage des assemblages hybrides composite-métal reste un enjeu important dans le domaine aéronautique compte tenu de son impact sur la tenue en service des assemblages structuraux. En service, les alésages réalisés sont fortement sollicités sous chargement cycle en matage. Les contraintes géométriques, dimensionnelles et d’état de surface imposées par les Bureaux d’Etude sont donc très exigeantes et nécessitent un process de fabrication extrêmement bien maitrisé sur l’ensemble des alésages réalisés. La détection automatique des matériaux lors d’une opération de perçage reste un point clef pour la mise en place des stratégies de smart-drilling intégrant de l’usinage auto-adaptatif. Dans le cadre de cette étude, une analyse dans le domaine temporel et fréquentiel des signaux d’efforts de coupe dans différentes configurations de perçage d’empilage hybride composite-métal est proposée. Dans un premier temps, une analyse via une représentation polaire des signaux d’efforts temporels permet de mettre en évidence l’effet des phénomènes d’usure sur l’évolution des signatures temporelles. Dans un second temps, une analyse fréquentielle des phénomènes vibratoires induits par les différents modes de coupe des fibres selon la stratification utilisée, permet de distinguer de manière plus fiable que dans le domaine temporel, les matériaux composites des matériaux métalliques. La méthode d’analyse fréquentielle proposée est appliquée sur différentes configurations (composite-métal, composite-composite avec différentes stratifications) afin de démontrer sa robustesse

Reverse blending : une réponse efficace au défi de la personnalisation de masse dans la production de granulés

International audienceMass customization, a major trend in modern economy, relies, in discrete production, on the alternative components assembly while it consists, in the continuous one, in the production of a sequence of batches of different products, which limits feasible diversity, increases transportation issues and therefore prevents economies of scale. In the context of sustainable agriculture, fertilizer producers must significantly increase the variety of their produced fertilizers; any deviation from the recommended formula, for a certain crop on a given soil, results in a loss of productivity and/or soil depletion. The disruptive solution of the Reverse Blending (RB) that we are proposing for this problem, is based on a delayed differentiation performed nearby end-users. It is an extension of the blending problem where inputs does not pre-exist and are to be defined, in number and composition, simultaneously with their use in blending to satisfy exactly outputs requirement. Of course, the number of the inputs to be produced must be as small as possible. RB formulation lays on a parametric quadratic problem. A real case study of this approach is provided.Dans la production manufacturière, la personnalisation de masse s’effectue par une combinaison de composants alternatifs montés sur une ligne d’assemblage. Dans l’industrie de process, elle est plus difficile car elle implique la fabrication successive de lots de produits différents, ce qui limite la diversité offerte en raison de l’inertie temporelle que cette production séquentielle implique. Dans ce contexte, la diversité croissante des flux à produire et transporter empêche toute économie d’échelle. Dans le cadre d’une agriculture durable, les producteurs d’engrais doivent accroître considérablement la variété des engrais produits, tout écart par rapport à la formule recommandée pour un couple « sol - culture », se traduisant par une perte de productivité et/ou un appauvrissement des sols. La solution disruptive du Reverse Blending (RB) que nous apportons à ce problème, repose sur une différenciation retardée réalisée à proximité des lieux de distribution et non sur les lieux de production. C’est une extension du problème de blending dans laquelle les inputs ne sont pas préexistants et doivent être définis, en nombre et en composition, simultanément à leur utilisation pour produire les engrais désirés. Sa formulation repose sur un programme quadratique paramétrique. Une illustration numérique de ce modèle est proposée sur un jeu de données réel

Modélisation de l’effet des impuretés de l’acide phosphorique sur la qualité physique des engrais phosphate d’ammonium

National audienceLa surveillance des propriétés physiques des engrais présente beaucoup d'intérêt à différents niveaux. Tous les problèmes liés au comportement des granulés (ségrégation, épandage, granulation, dureté ...) nécessitent une meilleure caractérisation des engrais pour les comprendre et/ou les prédire. La communauté scientifique est amenée à développer diverses approches de modélisation pour, d’une part, comprendre la dynamique des impuretés provenant de l’acide phosphorique lors de la fabrication des engrais et, d’autre part, évaluer l’efficacité des mesures et suivi des données de la production et des fluctuations de la qualité physique des engrais. Nous avons collecté et suivi pendant plusieurs mois les données des lignes de production d’engrais phosphatés (MAP). L’objectif de ce travail est de comprendre, à travers la modélisation en appliquant l'approche du réseau de neurones artificiels (ANN), l'effet des impuretés d'acide phosphorique sur la qualité physique des engrais tels que le rendement de granulation, la taille des grains et le diamètre moyen des granulés D50. Des modèles ont été construits en utilisant la régression linéaire multiple (MLR) et l'analyse en composantes principales (ACP)

Study of the Effect of Calcium Substitution by Magnesium in the Vitreous System 3P2O5-2K2O-(1 − x) CaO-x MgO

Phosphate glasses have potentially interesting properties that can be used in various applications. Recently, different studies are focusing on their dissolution behaviours that can be modified to suit some environmental applications, such as controlled-release fertilisers. In this work, magnesium had been suggested to improve the glass durability of 3P2O5-2K2O-(1 − x)CaO-xMgO glasses (0 ≤ x ≤ 1). Indeed, its effect on glass structure, thermal properties and most important dissolution behaviours were studied, in order to evaluate their suitability of being used as controlled-release fertilisers. Various compositions in which calcium was partially replaced by magnesium were prepared by melting at 800 °C. The samples were characterised by differential scanning calorimetry, density measurements, X-Ray diffraction, FTIR spectroscopy and Raman spectroscopy. The dissolution behaviours were investigated using inductively coupled plasma optical emission spectrometry ICP-OES, pH measurements and SEM. Substitution of calcium by magnesium reduced the glass density, owing to the lower atomic weight of magnesium compared to calcium, and caused an increase in glass transition and crystallisation temperatures. Magnesium substitution significantly improved the chemical durability of the glasses due to more covalent Mg–O bond than the Ca–O bond. This study demonstrated that 3P2O5-2K2O-0.3CaO-0.7MgO (x = 0.7) had a dissolution profile adequate to the criteria of controlled-release fertilisers and could be used to nourish the plants with phosphorus, potassium, calcium and magnesium

Innovative Formulations of Phosphate Glasses as Controlled-Release Fertilizers to Improve Tomato Crop Growth, Yield and Fruit Quality

Three phosphate glass compositions, VF1, VF2, and VF3, containing macro and micronutrients with different [K2O/(CaO+MgO)] ratio, were formulated to be used as controlled release fertilizers for tomato crop, depending on their chemical durability in water and their propriety with respect to the standards of controlled-release fertilizers. This study investigated the influence of [K2O/(CaO+MgO)] ratio variation on glass properties. For this, the elaborated glasses have undergone a chemical characterization using inductively coupled plasma atomic emission spectroscopy, a thermal characterization using differential thermal analysis, a physicochemical characterization based on density and molar volume measurements, and a structural characterization using Raman spectroscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction. In addition, the chemical durability was determined by measuring the percentage of weight loss and the pH. Results revealed that the glass structure and composition have the mean role in controlling the release of nutrients in water. By increasing [K2O/(CaO+MgO)] ratio, the dissolution rates of the glasses increased due to the shrinking in the rate of crosslinking between phosphate chains, accompanied with a diminution in transition and crystallization temperatures, and an increase in the molar volume. An agronomic valorization of VF1 and VF2 glass fertilizers, which showed dissolution profiles adequate to the criteria of controlled-release fertilizers, was carried out to evaluate their efficiency on tomato crops. These glass fertilizers improved soil mineral content and tomato performances in comparison to the control and NPK treatments with the distinction of VF2. The results highlight the effectiveness of these smart fertilizers toward their potential large-scale application to improve crop production and quality for high nutritional value foods

STATISTICAL STUDY AND MODELING OF THE EFFECT OF PHOSPHORIC ACID IMPURITIES ON THE PHYSICAL QUALITY OF AMMONIUM PHOSPHATE DETERMINED FROM THE PRODUCTION DATA

International audienceFertilizer producing entity, OCP group.SA, Jorf lasfar, BP118 – 24025 El Jadida, Maroc Ammonium phosphate fertilizer is produced by simple reaction (neutralization) between ammonia and phosphoric acid resulting in the formation of the basic salt.The knowledge of the physical properties of fertilizers presents a lot of interest at different level. All the problems dealing with the behavior of the particles (segregation, spreading, granulation, hardness…) need a better characterization of the fertilizers in order to understand and/or predict them.Several works were carried out to define and control the effect of impurities from phosphoric acid on the physicochemical properties of ammonium phosphates fertilizers. In the investigation of the influence of elements such as Fe, Al, MgO, F-, SiO2, Na2O, K2O and Cl- on fertilizer quality, we followed the production lines of Ammonium phosphate fertilizers for several months, even more than a year.The aim of the current work is the statistical study and modeling the effect of phosphoric acid qualities on the physical quality of fertilizers such as granulation yield, grain size, and the average diameter of granules D50, based on the analysis of data from different production lines by applying the Principal Components Analysis (PCA). In addition models were constructed using Multiple Linear Regression (MLR) and Artificial Neural Network (ANN)

Properties of Coated Controlled Release Diammonium Phosphate (DAP) Fertilizers Prepared with the Use of Bio‐based Amino Oil

International audienceIn an effort to enhance the efficiency of fertilizer use and minimize their negative impact on the environment, a novel biomass-based, functional controlled-release fertilizer was use to improve nutrient use efficiency and increase crop production systems for more sustainable agriculture practices. Here, biobased amino-oil (Priamine) mixtures were proposed as an outer coating with different layers for the control of phosphorus release from diammonium Phosphate (DAP). These hydrophobic coatings conferred excellent barrier properties and flexibility to coatings. The morphological characterization of the coated fertilizer was performed by Scanning Electronic Microscopy (SEM), and Electronic Diffraction X-ray (EDX) maping, and revealed the formation of a cohesive film and a good adhesion between DAP fertilizer and coating film. The release rate of nutrients (phosphate) in water was investigated by UV-Vis spectrophotometer. The effect of coating thickness was investigated on release time and diffusion coefficient of phosphor release in distilled water. Release time increased with the coating thickness. The diffusion coefficient of nutrient release decreased with the coating thickness. Compared with uncoated granule which is totally solubilized after less than 2 hours, the P release profiles of the coated granules reached the equilibrium stage approximatively after 98 and 126 hours when the DAP is coated with only Priamine single-layer (1L) and double-layer (2L), respectively. Moreover, the strategy adopted has successfully provided a very slow release and long-term availability of nutrients sources with biobased coating oil compared to uncoated fertilizer (DAP) and therefore exhibited promising application for sustainable development of modern agriculture and circular economic

Statistical Study and Modeling of the Effect of Phosphoric Acid Impurities on the Physical Quality of Ammonium Phosphate Determined from the Production Data Using Artificial Neural Network

International audienceThe monitoring of the physical properties of fertilizers presents a lot of interest at different levels. All the problems related to the behavior of the granules (segregation, spreading, granulation, hardness…) need a better characterization of the fertilizers in order to understand and/or predict them.The scientific community is led to develop a variety of modeling approaches for, on the one hand, the understanding of the dynamics of impurities originating from phosphoric acid during the manufacture of fertilizers, and on the other hand, the evaluation of the effectiveness of measurements and data monitoring from production and the fluctuations in the physical quality of the fertilizers that follow. In this investigation of the influence of elements such as Fe, Al, Mg, F-, Si, Na, K and Cl on fertilizer quality, we gathered and followed-up data from production lines of Ammonium phosphate fertilizers for several months. The aim of the current work is the statistical study and modeling of the phosphoric acid impurities effect on the physical quality of fertilizers such as granulation yield, grain size, and the average diameter of granules D50, based on the analysis of data from different production lines by applying the Artificial Neural Network (ANN) approach. In addition models, were constructed using Multiple Linear Regression (MLR) and Principal Components Analysis (PCA)