Numerical and experimental analyses of resin infusion manufacturing processes of composite materials

Liquid resin infusion (LRI) processes are promising manufacturing routes to produce large, thick, or complex structural parts. They are based on the resin flow induced, across its thickness, by a pressure applied onto a preform/resin stacking. However, both thickness and fiber volume fraction of the final piece are not well controlled since they result from complex mechanisms which drive the transient mechanical equilibrium leading to the final geometrical configuration. In order to optimize both design and manufacturing parameters, but also to monitor the LRI process, an isothermal numerical model has been developed which describes the mechanical interaction between the deformations of the porous medium and the resin flow during infusion.1, 2 With this numerical model, it is possible to investigate the LRI process of classical industrial part shapes. To validate the numerical model, first in 2D, and to improve the knowledge of the LRI process, this study details a comparison between numerical simulations and an experimental study of a plate infusion test carried out by LRI process under industrial conditions. From the numerical prediction, the filling time, the resin mass and the thickness of the preform can be determined. On another hand, the resin flow and the preform response can be monitored by experimental methods during the filling stage. One key issue of this research study is to highlight the changes in major process parameters during the resin infusion stage, such as the temperature of the preform and resin, and the variations of both thickness and fiber volume fraction of the preform. Moreover, this numerical/experimental approach is the best way to improve our knowledge on the resin infusion processes, and finally, to develop simulation tools for the design of advanced composite parts

Monitoring the resin infusion manufacturing process under industrial environment using distributed sensors

A novel direct approach to detect the resin flow front during the Liquid Resin Infusion process under industrial environment is proposed. To detect the resin front accurately and verify the results, which are deduced from indirect micro-thermocouples measurements, optical fiber sensors based on Fresnel reflection are utilized. It is expected that the results derived from both techniques will lead to an improvement of our understanding of the resin flow and in particular prove that micro-thermocouples can be used as sensors as routine technique under our experimental conditions. Moreover, comparisons with numerical simulations are carried out and experimental and simulated mold filling times are successfully compared.Comment: JM-JCM-46.pd

Évaluation des connaissances des maîtres de stage de Paris XIII dans la prise en charge des patients hypertendus suite aux recommandations de l'HAS de 2005

L hypertension artérielle est la pathologie la plus courante en médecine ambulatoire ; ainsi 1 consultation sur 5 y est consacrée. Pourtant, en 2009, sur les 16 millions de patients hypertendus, seuls 40% étaient traités et équilibrés. Nous avons donc voulu évaluer les connaissances des maîtres de stage de la faculté de médecine de Bobigny par rapport aux recommandations faites par l HAS en 2005, ainsi que leur mise en pratique au moyen d un questionnaire et de 2 cas cliniques. Cette évaluation s est faite au cours du premier semestre 2010 lors d entretiens menés aux cabinets médicaux des maîtres de stage. Nous avons pu constater qu un certain nombre de maîtres de stage ne connait pas correctement les recommandations de l HAS, ce qui les empêche d évaluer entre autre le risque cardiovasculaire global du patient avant une décision thérapeutique. Par ailleurs, nous avons remarqué que leurs connaissances n étaient pas toujours appliquées. De ces résultats, nous avons élaboré des réponses et des solutions pour améliorer la formation des maîtres de stage et la prise en charge des patients hypertendus.Arterial hypertension is the most current pathology in ambulatory medicine. In 2009, out of the 16 million hypertensive patients only 40% were treated and balanced. So we evaluated knowledge of the Masters of the training course of the Faculty of Medicine of Bobigny following the recommendations made by the HAS in 2005, like their practical application by means of a questionnaire and of 2 clinical cases. This evaluation was done in the first half of 2010 during talks taking place at their medical surgery. We noticed that a certain number of Masters of training courses are not well informed of the recommendations of the HAS, which prevents them from evaluating the total cardiovascular risk of the patient before a therapeutic decision. In addition, we noticed that their knowledge was not always put into practice. From these results, we have worked out solutions to improve the formation of the Masters of training courses and the medical treatment of the hypertensive patientsPARIS13-BU Serge Lebovici (930082101) / SudocSudocFranceF

Etude numérique et expérimentale de procédé d'élaboration des matériaux composites par infusion de résine (LRI)

Les procédés de fabrication dits LRI (Liquid Resin Infusion) sont prometteurs pour produire des pièces de grandes dimensions ou épaisseur, et des structures complexes, mais ils sont encore difficiles à maîtriser et à contrôler.  Pour optimiser les paramètres importants contrôlant ces procédés, une approche numérique / expérimental spécifique est nécessaire. Les modèles utilisés sont de type fluide-poroelasticité en grande déformation

Characterization of Liquid Resin Infusion (LRI) filling by fringe pattern projection and in situ thermocouples

International audiencePrepregs are not alone suited to the manufacturing of new types of aircraft structural parts that tend to be thicker and have more complex shapes. Direct processes called Liquid Composites Moulding (LCM), like Resin Transfer Moulding (RTM) or Resin Infusion Process (LRI: Liquid Resin Infusion, RFI: Resin Film Infusion) are now available. Particular attention is paid here to LRI process that looks very promising. In order to optimize both the design and manufacturing parameters in LRI processes, a general model to analyze the isothermal fluid flow through highly compressible porous media such as fibrous preforms has been recently proposed [1], [2] and [3]. To validate the model and to improve the knowledge of the LRI process, an experimental approach is proposed. Two different measurement techniques, micro-thermocouple sensors and fringe projection technique, have been used to characterize the process. It appears that results derived from both techniques are in agreement and support the assumption that the resin flow occurs mainly transversely to the preform plane