This investigation completed the verification of a three-dimensional resin transfer molding/resin film infusion (RTM/RFI) process simulation model. The model incorporates resin flow through an anisotropic carbon fiber preform, cure kinetics of the resin, and heat transfer within the preform/tool assembly. The computer model can predict the flow front location, resin pressure distribution, and thermal profiles in the modeled part. The formulation for the flow model is given using the finite element/control volume (FE/CV) technique based on Darcy's Law of creeping flow through a porous media. The FE/CV technique is a numerically efficient method for finding the flow front location and the fluid pressure. The heat transfer model is based on the three-dimensional, transient heat conduction equation, including heat generation. Boundary conditions include specified temperature and convection. The code was designed with a modular approach so the flow and/or the thermal module may be turned on or off as desired. Both models are solved sequentially in a quasi-steady state fashion. A mesh refinement study was completed on a one-element thick model to determine the recommended size of elements that would result in a converged model for a typical RFI analysis. Guidelines are established for checking the convergence of a model, and the recommended element sizes are listed. Several experiments were conducted and computer simulations of the experiments were run to verify the simulation model. Isothermal, non-reacting flow in a T-stiffened section was simulated to verify the flow module. Predicted infiltration times were within 12-20 percent of measured times. The predicted pressures were approximately 50 percent of the measured pressures. A study was performed to attempt to explain the difference in pressures. Non-isothermal experiments with a reactive resin were modeled to verify the thermal module and the resin model. Two panels were manufactured using the RFI process. One was a stepped panel and the other was a panel with two `T' stiffeners. The difference between the predicted infiltration times and the experimental times was 4 to 23 percent. / Master of Science

This investigation explored the feasibility of recently developed toughened cyanate ester networks as candidate materials for high performance composite matrix applications. The resin investigated was a Bisphenol-A cyanate ester toughened with hydroxy functionalized phenolphthalein based amorphous poly(arylene ether sulfone). The thermoplastic modified toughened networks exhibited improvement in the fracture toughness over the base cyanate ester networks without significant reductions in mechanical properties or glass transition temperature. Void free, unidirectional carbon fiber prepreg was successfully manufactured with the toughened cyanate resin using a solventless hot-melt technique. The resin mass fraction of the prepregs was between 31 and 35%. The carbon fiber, toughened cyanate ester prepreg was fabricated into composite panels for mechanical and physical testing. The cure cycle used to manufacture the composite laminates was developed with the aid of a process simulation model developed by Loos and Springer. In order to accurately simulate the resin curing and flow processes, the cure reaction kinetics and melt viscosity was characterized as a function of temperature and degree of cure and input into the simulation model. The model generated cure cycle was used in the manufacture 8-ply unidirectional and 16-ply quasi-isotropic composite laminates. The manufactured laminates were well consolidated to the specified fiber volume fraction between 59 and 60%. Photomicrographs showed that the laminates are void free, the fiber and resin distribution is uniform and fiber wet-out is very good. Mechanical tests were performed to measure the impact damage resistance and shear properties of the toughened cyanate ester resin composites. The results show improvements in impact damage resistance compared with the commonly used hot-melt epoxy resin composites. The influence of processing on performance was observed from the results of shear tests. Carbon fabric composite panels were manufactured by liquid molding processes (resin transfer molding and resin film infusion), with a series of four toughened cyanate ester resins generated by varying the concentration and the molecular weight of the toughener. The panels were subjected to physical, damage tolerance, and fracture toughness tests. The results of physical testing indicate consistently uniform quality, and the void content was found to be less than 2%. The toughened cyanate ester composites exhibited significantly improved impact damage resistance and tolerance compared with hot-melt epoxy systems. Marked increase in the mode II fracture toughness were observed with an increase in the concentration and the molecular weight of the toughener. / Ph. D.

Le procédé Resin Transfer Molding est une technologie de fabrication de pièces en matériaux composites. Une compréhension et une modélisation des phénomènes physiques qui interviennent dans certaines étapes de la fabrication apportent une contribution importante à la maîtrise de ce procédé. Les travaux abordés dans cette étude se situent dans le cadre d'un programme plus général visant le contrôle et le pilotage du RTM. Tout d'abord, une caractérisation de la perméabilité des renforts dans la direction perpendiculaire aux plis va compléter les résultats obtenus dans des études préalables sur les perméabilités planes. Ensuite, nous étudierons de près les transferts thermiques durant l'injection et la cuisson. Pour cela, plusieurs étapes sont nécessaires: caractérisation des propriétés thermiques (avec notamment le développement d'un montage destiné à mesurer les conductivités thermiques dans le plan des fibres), étude théorique et étude expérimentale à l'aide d'un moule instrumenté. Des simulations numériques permettront alors de valider les modèles développés. Ces travaux devront ensuite servir de base à l'amélioration du logiciel de simulation LCMFLOT. Enfin, une première étape vers l'optimisation du remplissage a été réalisée afin de pouvoir piloter les machines d'injection en imposant une vitesse d'imprégnation constante pendant le remplissage. Cette optimisation est basée sur l'exploitation des résultats de simulation.

Baigiamajame magistro darbe suprojektuotos ir pagamintos dviejų rūšių šviesos koncentratorinės sistemos: jungtinė parabolinė ir sistema su Frenelio lęšiu. Atlikta saulės elementų efektyvumo analizė, išnagrinėtos šviesą koncentruojančių sistemų rūšys bei aptarti jų optiniai parametrai. Frenelio lęšis ir koncentratorinių sistemų laikančiosios konstrukcijos pagamintos vakuuminio formavimo būdu, ieškant pigesnės gamybos technologijos. Baigiamajame darbe atlikti optinio pralaidumo ir lūžio rodiklio, matomos šviesos bangų ilgių ruože, tyrimai bei saulės elementų, esančių šviesos koncentratorinėse sistemose,voltamperinių ir voltvatinių charakteristikų tyrimai. Iš tyrimų rezultatų nustatyti šviesos koncentravimo laipsniai. Darbe diskutuojama apie pigių optinių sistemų galimus pritaikymus ir jų tobulinimo būdus. Išnagrinėjus teorinę ir praktinę dalis, pateiktos išvados ir pasiūlymai. Darbą sudaro 8 dalys: įvadas, saulės elementų efektyvumo ribos, saulės šviesos koncentratoriai ir jų panaudojimas fotoelektrinėse sistemose, eksperimentinių tyrimų metodika, prototipų gamyba, eksperimentiniai tyrimai, išvados, literatūros sąrašas. Darbo apimtis – 82 p. teksto be priedų, 95 pav., 13 lent., 22 bibliografiniai šaltiniai. Atskirai pridedami darbo priedai. / Concentrated PV systems (compound parabolic and Fresnel CPV) have been designed and investigated. The efficiency of solar cells and the types of light concentrated systems have been analyzed and their optical parameters have been discussed. Fresnel lens and the CPV system holding structure have been fabricated by means of vacuum forming machine in this way making the technology of production less expensive. Optical transmittance and refractive index of Fresnel lens were measured in the range of visible light wavelengths. Current-voltage and voltage-power characteristics of solar cells built inside the CPV systems were investigated, based on results the degree of light concentration by Fresnel lens and compound parabolic CPV has been determined. Some discussions regarding possible applications of concentrated PV systems containing the Fresnel lens as well as possible ways of CPV design improvements are given in current work. After analysed theoretical and practical parts, conclusions and suggestions are proposed. Thesis structure: introduction, theoretical and experimental parts, results of experiments, conclusions and references. Thesis consist of: 82 p. text without appendixes, 95 pictures, 13 tables, 22 bibliographical entries. Appendixes included.

Les matériaux composites ont connu ces dernières années une forte croissance, croissance aujourd'hui renforcée par les nouvelles normes européenne visant à diminuer les émissions CO2 d'ici 2020. La réalisation de pièces complexes peut poser de nombreuses problématiques de fabrication comme la formation de zones sèches, ou la création de distorsions géométriques. Les origines de ces problématiques sont souvent liées à un manque de connaissance et de maîtrise des phases d'imprégnation des renforts et de cuisson du matériau. L'amélioration de la robustesse des procédés nécessite d'avoir une connaissance fine des phénomènes physiques qui ont lieu lors de l'élaboration. Dans cette perspective, les procédés d'élaboration de matériaux composites ont été étudiés à travers la mise en place d'un démonstrateur de laboratoire dans le cadre du projet LCM Smart. Ce pilote d'injection a permis de valider des solutions d'instrumentation, à partir de capteurs innovants (OFS) développés en partenariat avec le laboratoire d'optique Hubert Curien.L'application de cette instrumentation dans le cadre du suivi du procédé RTM a démontré les capacités des OFS pour le suivi des caractéristiques physiques de la pièce (le front d'écoulement, la température, les déformations résiduelles et le degré de cuisson). La comparaison des caractéristiques mesurées avec des simulations numériques effectuées en collaboration avec ESI, a montré une bonne corrélation.Enfin, l'instrumentation a permis de mettre en évidence l’intérêt d’un outillage composite en HexTool pour la réduction des contraintes résiduelles liées à l'interaction outil/pièce. / A significant growth in production and consumption of composite materials can be seen recently; growth reinforced by the new European standards, aimed at reducing CO2 emissions by the year 2020.The producing of complex parts can cause many difficulties for manufacturing because of their geometries and / or their constituents (using of various materials). For example, dry zones or geometric distortion formation. The origins of these difficulties are often related to a lack of knowledge and control of the reinforcement's impregnation phases and material curing.Improving the robustness of the processes demands a detailed knowledge of physical phenomena that occur during the producing. For this, we studied the composite materials production through the implementation of a laboratory demonstrator in the project LCM Smart. This pilot injection was used to validate instrumentation solutions, from innovative sensors (OFS) developed in partnership with the optical laboratory Hubert Curien. The application of this instrumentation in the context of RTM process monitoring in the development of simple parts has demonstrated the capabilities of OFS to control physical characteristics of the part (the flow front, temperature, residual strain and curing degree). The comparison of the measured characteristics with numerical simulations carried out in collaboration with ESI showed a good correlation.Finally, instrumentation has demonstrated the capacity of composite tool made by HexTool to minimize the residual stresses due to the tool/part interaction.

ALes travaux présentés sont une contribution à l’élaboration de composites à matrices thermoplastiques (TP) par un procédé de type Liquid Composite Molding non réactif pour l’industrie automobile. La thèse a été effectuée dans le cadre du projet ANR TAPAS (ThermoplAstic Process for Automotive composite Structure) et s’est focalisée sur la mise en œuvre de plaques composites en renfort continu injectées avec des matrices polyamides 6,6 (PA 6,6) de hautes fluidités par Resin Transfer Molding. Le premier objectif est porté sur l’optimisation des cadences d’injection à travers l’étude de la perméabilité de préformes unidirectionnelles (UD) en fibres de verre et à hauts modules mécaniques. L’architecture de ces UD a ainsi été modifiée de manière à faciliter les écoulements. La perméabilité des différents tissus a pu être évaluée par un couplage entre des mesures expérimentales et une modélisation analytique basée sur un raisonnement à deux échelles de pores : l’écoulement intra et inter-torons. Le deuxième objectif sur lequel les travaux de thèse se sont concentrés s’est reposé sur la maitrise de l’état d’imprégnation par le bais d’une étude complète sur les phénomènes qui se déroulent à l’interface entre la fibre et la matrice à haute température. Plusieurs viscosités et formulations du PA 6,6 ainsi qu’un traitement appliqué sur le verre ont pu être caractérisés et discutés en termes de mouillabilité et d’adhésion. Enfin, la dernière partie du manuscrit présente les résultats obtenus sur les plaques mises en œuvre par RTM-TP en injection in-plane. Les conditions optimales de fonctionnement ainsi que les aspects de saturation, de santé matière et des propriétés mécaniques sont ensuite présentés et discutés. / The present work is a contribution to the thermoplastic composites manufacturing by a non-reactive Liquid Composite Molding process for the automotive industry. The thesis was carried out by the « ANR TAPAS » project (Thermoplastic Process for Automotive Composite Structure) and was focused on the elaboration of continious-fiber reinforced composites plates injected with a high-fluidity polyamide 6,6 (PA 6,6) by the Resin Transfer Molding process. The first goal was focused on increasing injection rates through the study of the in-plane permeability of unidirectional (UD) glass fiber fabrics with high mechanical modulus (HM). Experiments and modelling results showed that the permeability of these UD has been enhanced by modifying specific structural parameters of their architecture. The analytical model developped and used is based on a flow distribution according two differents scales of porosity : in and inter-yarns. The second part of the work was focused on the understanding of phenomenas that take place at the interface created between glass fiber and the matrix during the impregnation step. The wettability and adhesion of molten PA 6,6 dropped on a glass substrate is studied at different processing temperature. The last part introduce the thermoplastic composite plates elaborated by RTM-TP process. The optimum operating conditions as well as preforms saturation and mechanical properties are also studied and discussed.

Les transducteurs ultrasonores font l'objet de nombreux développements en contrôle non-destructif (CND) industriel. Utilisé ponctuellement et périodiquement, le CND ultrasonore permet d'établir des diagnostics sur la santé des matériaux. La caractérisation ultrasonore en temps réel constitue un outil de surveillance de l'évolution des propriétés physiques lors de la fabrication des matériaux composites. Dans ce contexte, des études sont menées au LOMC pour optimiser le procédé de fabrication des matériaux composites par RTM (Resin Transfer Molding) afin d’améliorer la qualité du produit. Ce travail de thèse consiste à développer des méthodes ultrasonores pour le suivi des propriétés viscoélastiques d’un composite pendant la phase de production. Les propriétés viscoélastiques sont étudiées à l’aide de modèles théoriques, de simulations numériques et de résultats expérimentaux. Des études de calibration ont été menées afin d’étudier les facteurs d’influence sur le suivi de propriétés ultrasonores lors de la mise en oeuvre d’un procédé RTM. Le suivi des paramètres viscoélastiques de résines époxy est effectué dans un premier temps à basse température au cours d'une polymérisation isotherme et d’une post-cuisson. Ensuite, une approche basée sur la méthode de caractérisation en émission/transmission a été développée afin d’étudier le comportement à haute température. La modélisation de la réponse électroacoustique par série de Debye (DSM) a été effectuée en se basant sur des approches analytiques. L’utilisation des transducteurs multiéléments permet la localisation et le dimensionnement de défauts lors du déplacement de fibres de carbone dans une résine liquide, entre des moules. / The developments based on ultrasonic transducers are nowadays numerous in the industrial non-destructive testing (NDT). Used punctually and periodically, the ultrasonic NDT is used for health diagnostics of materials. Ultrasonic characterization in real time allows a physical properties monitoring during the manufacturing of composite materials. In this context, studies are conducted in LOMC in view to optimize the manufacturing process of composite materials using RTM (Resin Transfer Molding) in order to improve the product quality. This work consists to develop ultrasonic methods for the monitoring of viscoelastic properties during the production phase of composites. The viscoelastic properties are studied using theoretical models, numerical simulations and experimental measurements. Calibration studies were carried out to study the influencing factors on the monitoring of ultrasonic properties during the RTM process. The monitoring of viscoelastic parameters of epoxy resins is performed in a first time at low temperature during an isothermal polymerization and a post-curing. Then, an approach based on the transmission mode characterization was developed to study high-temperature behavior. Based on analytical approaches, the electroacoustic response was simulated by Debye series method (DSM). The use of phased array transducers was investigated for the location and sizing of defects during the movement of the carbon fiber in a liquid resin between the molds.

This Master´s thesis is about ways of packages of integration circuits and modules. Especially it´s about non-hermetic types of packages. One part of this paper are basic information about packaging and aspects in design of package. Next parts are design of test samples, which are package to epoxide powder material. Based on the results of the tests method, it will propose, where the technology will be used.

Tillämpningen av fiberförstärkt polymerkomposit har senaste decenniet ökat kraftigt inom flertalet högteknologiska branscher. Trots framgången är förekomsten av tillverkningsinducerade avvikelser fortfarande en utmaning. Avvikelserna försämrar materialets mekaniska egenskaper och förkortar dess livslängd, vilket orsakar kassationer, miljöbelastningar och försvårad produktetablering för industriaktörer. ABB Composites i Piteå står inför en liknande situation. Företaget producerar cylindriska isolatorer i fiberförstärkt komposit till högspänningsindustrin, och behöver utreda förekomsten av en specifik avvikelse, som under senaste tre åren medfört omfattande kvalitetsbristkostnader. Produkten tillverkas genom vakuuminjicering där en hartsblandning impregnerar en glasfiberform, för att sedan övergå från flytande till fast form genom en exoterm reaktion. Hartsblandningens reaktionsförlopp har länge misstänkts påverka avvikelsernas förekomst, men har inte bekräftats, på grund av flera svårkontrollerade egenskaper. Examensarbetets syfte har därför varit att utreda om hartsblandningens egenskaper påverkar förekomsten av tillverkningsinducerade avvikelser vid tillverkning av cylindriska isolatorer. Arbetet har bedrivits som ett Sex Sigma-projekt enligt problemlösningsmetodiken DMAIC. Ett blandningsexperiment med sex komponenter genomfördes i laborationsmiljö där en datagenererad design med 36 delförsök tillämpades, varav sex stycken egenskaper hos hartsblandningen undersöktes. Experimentet påvisade att samtliga egenskaper var möjliga att styra genom att förändra proportionerna av ingredienserna. Däremot visade sig flera av egenskaperna vara korrelerade och kan därav inte justeras oberoende av varandra. Kunskapen användes till att utveckla och testa två nya varianter av hartsblandningen vid tillverkning av cylindriska isolatorer. Resultatet bekräftade att hartsblandningens egenskaper signifikant påverkar förekomsten av tillverkningsinducerade avvikelser. En viss kombination av egenskaperna som kännetecknade ett långsamt reaktionsförlopp minskade förekomsten av avvikelser på isolatorerna med 99.3 procent i jämförelse med den ordinarie hartsblandningen. Förbättringen förväntas medföra betydelsefulla besparingar, ökad konkurrenskraft och förhöjd kvalitetsmedvetenhet för ABB Composites. Examensarbetets kunskapsbidrag anses också betydelsefullt för kompositindustrin i strävan mot fortsatt reducering av tillverkningsinducerade avvikelser. / The application of fibre-reinforced polymer composites (FRPC) have during the last decades increased in many high-tech industries. Despite the success, the existence of manufacturing-induced deviations has been a long-standing challenge. These deviations affect the lifetime and the mechanical properties of the composite, which in turn lead to scrap of products and environmental impact, obstructing market exploitation for industry stakeholders. ABB Composites in Piteå is facing a similar scenario. The company produces cylindrical insulators in fibre-reinforced composite for the high-voltage industry and need to investigate a specific deviation, which has caused extensive costs during the last three years. The product is manufactured through vacuum assisted resin transfer molding (VARTM), where a resin blend impregnates a fibreglass preform, as the resin cures and transforms from liquid to solid form through an exothermic reaction. One suspected cause for the deviation has been the curing process of the resin. However, it is dependent on several difficult-to-control characteristics and is yet to be confirmed. The purpose of this thesis has therefore been to investigate whether the characteristics of the resin blend affects the occurrence of manufacturing-induced deviations while producing cylindrical insulators. The work has been conducted as an internal Six Sigma-project following the DMAIC improvement cycle. A mixture experiment with six components was performed, using a computer-generated design with 36 runs, in which six characteristics of the resin blend were examined. The experiment proved that all characteristics could be controlled by changing the proportions of the design factors. However, many of the characteristics were correlated, implying that the characteristics cannot be independently controlled. The knowledge from the experiment were used to develop two new resin blends, which were infused to cylindrical insulators in regular production environment. The result confirmed that the characteristics of the resin blend significantly affects the quality of the insulator. One of the blends, which represented a slower curing process, reduced the deviations by 99.3 percent in relation to the original blend. The improvement is expected to generate substantial savings, increased competitiveness and enhanced quality awareness for ABB Composites. Possible contributions to the industry are related to the development of a method to experimentally investigate the resin blend with the objective of reducing manufacturing-induced deviations.

Experimentation exploring the movement of voids within carbon fiber reinforced plastics was performed using fluorescent dye infused into the laminates observed through a transparent mold under ultraviolet light. In situ photography was used as an inspection method for void content during Resin Transfer Molding for these laminates. This in situ inspection method for determining the void content of composite laminates was compared to more common ex-situ quality inspection methods i.e. ultrasonic inspection and cross-section microscopy. Results for localized and total void count in each of these methods were directly compared to test samples and linear correlations between the three test methods were sought. Test coupons were then cut from these laminates and were used to calculate the interlaminar shear strength at certain locations throughout the laminates. Although this research did not adequately observe correlations between results obtained from ultrasonic C-scans, cross-sectional microscopy and in situ photography of the surface, it was seen that the fluid dynamics of the thermosetting epoxy used in this experimentation correlated to results obtained from previous experimentation performed by students at Brigham Young University using vegetable oil as a substitute for resin.