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Auswahl der wissenschaftlichen Literatur zum Thema „PEKK composite“
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Zeitschriftenartikel zum Thema "PEKK composite"
1
Rauch, Angelika, Sebastian Hahnel, Elena Günther, Wolfgang Bidmon und Oliver Schierz. „Tooth-Colored CAD/CAM Materials for Application in 3-Unit Fixed Dental Prostheses in the Molar Area: An Illustrated Clinical Comparison“. Materials 13, Nr. 24 (08.12.2020): 5588. http://dx.doi.org/10.3390/ma13245588.
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The aim of this study was to compare the clinical properties of tooth-colored computer-aided design/computer-aided manufacturing (CAD/CAM) materials for the fabrication of a 3-unit fixed dental prostheses (FDPs) in the same clinical scenario. A 53-year-old female patient was supplied with a 3-unit FDP to replace a second premolar in the upper jaw. Restorations were fabricated from 3 mol%, 4 mol%, and 5 mol% yttrium oxide zirconia, zirconia with translucency gradient, indirect composite resin, polyetheretherketone (PEEK), and polyetherketoneketone (PEKK). Milling time, weight, and radiopacity were investigated. Esthetics were examined following the US Public Health Service criteria (USPHS). The milling time for zirconia was twice as high as for the indirect composite resin, PEEK, or PEKK. The latter materials had a weight of 2 g each, while zirconia restorations yielded 5 g. Zirconia presented intense radiopacity. PEEK and PEKK required veneering and an opaquer was applied to the PEKK framework. All FDPs showed acceptable esthetics. PEEK and PEKK restorations were featured by a grayish shimmering. A variety of CAD/CAM materials are available to fabricate 3-unit FDPs with esthetically acceptable results. In the esthetic zone, PEEK and PEKK require veneering and an opaquer might be applied. Milling time, weight, and radiopacity were relatively high for zirconia FDPs.
2
Wang, Quanbin, Deli Jia, Xiaohan Pei, Xuelian Wu, Fan Xu, Huixiong Wang, Minghao Cao und Haidong Chen. „Investigation of Electromagnetic Pulse Compaction on Conducting Graphene/PEKK Composite Powder“. Materials 14, Nr. 3 (30.01.2021): 636. http://dx.doi.org/10.3390/ma14030636.
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Polymer-composite materials have the characteristics of light weight, high load, corrosion resistance, heat resistance, and high oil resistance. In particular, graphene composite has better electrical conductivity and mechanical performance. However, the raw materials of graphene composite are processed into semi-finished products, directly affecting their performance and service life. The electromagnetic pulse compaction was initially studied to get the product Graphene/PEKK composite powder. Simultaneously, spark plasma sintering was used to get the bars to determine the electrical conductivity of Graphene/PEKK composite. On the basis of this result, conducting Graphene/PEKK composite powder can be processed by electromagnetic pulse compaction. Finite element numerical analysis was used to obtain process parameters during the electromagnetic pulse compaction. The results show that discharge voltage and discharge capacitance influence on the magnetic force, which is a main moulding factor affecting stress, strain and density distribution on the specimen during electromagnetic pulse compaction in a few microseconds.
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Modi, Vedant, Aswani Kumar Bandaru, Karthik Ramaswamy, Conor Kelly, Conor McCarthy, Tomas Flanagan und Ronan O’Higgins. „Repair of Impacted Thermoplastic Composite Laminates Using Induction Welding“. Polymers 15, Nr. 15 (29.07.2023): 3238. http://dx.doi.org/10.3390/polym15153238.
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The lack of well-developed repair techniques limits the use of thermoplastic composites in commercial aircraft, although trends show increased adoption of composite materials. In this study, high-performance thermoplastic composites, viz., carbon fibre (CF) reinforced Polyetherketoneketone (PEKK) and Polyether ether ketone (PEEK), were subjected to low-velocity impact tests at 20 J. Post-impact, the damaged panels were repaired using an induction welder by applying two different methods: induction welding of a circular patch to the impacted area of the laminate (RT-1); and induction welding of the impacted laminates under the application of heat and pressure (RT-2). The panels were subjected to compression-after-impact and repair (CAI-R), and the results are compared with those from the compression-after-impact (CAI) tests. For CF/PEKK, the RT-1 and RT-2 resulted in a 13% and 7% higher strength, respectively, than the value for CAI. For CF/PEEK, the corresponding values for RT-1 and RT-2 were higher by 13% and 17%, respectively. Further analysis of the damage and repair techniques using ultrasonic C-scans and CAI-R tests indicated that induction welding can be used as a repair technique for industrial applications. The findings of this study are promising for use in aerospace and automotive applications.
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Premanand, Aravind, Mario Prescher, Michael Rienks, Lutz Kirste und Frank Balle. „Online and Ex Situ Damage Characterization Techniques for Fiber-Reinforced Composites under Ultrasonic Cyclic Three-Point Bending“. Polymers 16, Nr. 6 (13.03.2024): 803. http://dx.doi.org/10.3390/polym16060803.
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With ultrasonic fatigue testing (UFT), it is possible to investigate the damage initiation and accumulation from the weakest link of the composite material in the very high cycle fatigue (VHCF) regime in a shorter time frame than conventional fatigue testing. However, the thermal influence on the mechanical fatigue of composites and the scatter in fatigue data for composites under ultrasonic cyclic three-point bending loading still need to be investigated. In this study, we conducted interrupted constant-amplitude fatigue experiments on a carbon-fiber satin-fabric reinforced in poly-ether-ketone-ketone (CF-PEKK) composite material. These experiments were carried out using a UFT system, which operates at a cyclic frequency of 20 kHz with a pulse–pause sequence. Various parameters, such as the CF-PEKK specimen’s surface temperature, acoustic activity, and the ultrasonic generator’s input resonance parameters, were measured during cyclic loading. During experiment interruption, stiffness measurement and volumetric damage characterization in the CF-PEKK specimens using 3D X-ray microscopy (XRM) were performed. The locations of damage initiation and accumulation and their influence on the changes in in situ parameters were characterized. Under fixed loading conditions, damage accumulation occurred at different locations, leading to scattering in fatigue life data. Further, the damage population decreased from the surface to the bulk of the composite material.
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Menini, Maria, Francesca Delucchi, Francesco Bagnasco, Domenico Baldi, Luigi Canullo, Paolo Setti, Marco Migliorati, Enrico Simetti und Paolo Pesce. „Shock Absorption Capacity of High-Performance Polymers for Dental Implant-Supported Restorations: In Vitro Study“. Dentistry Journal 12, Nr. 4 (17.04.2024): 111. http://dx.doi.org/10.3390/dj12040111.
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Background: Restorative materials might significantly affect load transmission in peri-implant bone. The aim of the present study is to evaluate the shock absorption capacity of two different polymeric materials to be used for implant-supported prostheses. Methods: A masticatory robot was used to compare the shock absorption capacity of veneered and non-veneered polyetherketoneketone (PEKK), Pekkton®ivory (Cendres+Mètaux), and the glass fiber-reinforced composite (GFRC), TRINIATM (Bicon). Five identical sample crowns for each of the three groups were tested. Forces transmitted at the simulated peri-implant bone were recorded and statistically analyzed. Results: The statistical analysis of forces transmitted at the simulated dental implant revealed significant differences between the materials tested and between these materials and zirconia, glass ceramic, composite resin, and acrylic resin. Only differences between PEKK and veneered PEKK and between PEKK and one of the previously tested composite resins were not statistically significant. PEKK samples demonstrated significantly greater shock absorption capacity compared to GFRC. Conclusions: PEKK revealed optimal shock absorption capacity. Further studies are needed to evaluate its efficacy in the case of long-span prostheses with reduced prosthetic volume.
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Jin, Jianghai, Yuequan Wang, Jiaqi Shi und Yu Liu. „CF/PEKK advanced pultrusion thermoforming process temperature field simulation“. Journal of Physics: Conference Series 2566, Nr. 1 (01.08.2023): 012126. http://dx.doi.org/10.1088/1742-6596/2566/1/012126.
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Abstract Advanced pultrusion molding technology is one of the composite molding processes. It has unique advantages in the automated manufacturing of long trusses and long beam components. Thermoplastic composites are becoming popular for research in many fields such as aerospace because of their room-temperature storage and secondary use. Since the temperature history is critical to the molding quality of thermoplastic composites, the temperature field variation of CF/PEKK composites in the advanced pultrusion thermoforming process has been explored in the context of studying the advanced pultrusion molding process of thermoplastic composites in this paper. By constructing a 3D model of the temperature field and setting up a complete solution scheme in ANSYS simulation software, the simulated temperature field data were obtained, and a real-time temperature monitoring platform was set up to obtain the measured temperature data, and the comparison showed that the two temperature profiles fit well, which proved the applicability of the model and solution scheme to this study.
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Xu, Fan, Ming Gao, Hui-Xiong Wang, Xue-Lian Wu, Hong Liu, Chao Ma, Quan-Tong Yao und Hui-Yan Zhao. „Effect of Discharge Voltage on the Microstructure of Graphene/PEKK Composite Samples by Electromagnetic Powder Molding“. Polymers 15, Nr. 15 (31.07.2023): 3256. http://dx.doi.org/10.3390/polym15153256.
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The light weight, electrical conductivity, environmental friendliness, and high mechanical properties of graphene/PEKK composites make them popular in biomedical, electronic component and aerospace fields. However, the compaction density and carbonization of the specimen influence the microstructure and conductivity of the graphene/PEKK composite prepared by in situ polymerization, so electromagnetic-assisted molding was used to manufacture products to avoid carbonization and enhance the compaction density. The effects of different discharge voltages on the microstructure of the formed graphene/PEKK specimens were compared. Increasing the discharge voltage will lead to a closer distribution of flake graphene in the matrix to improve the compaction density, mechanical performance and conductivity. At the same time, the numerical analysis model was validated by comparison with the compaction density of the experimental results. Based on this research, the stress/strain distribution on the specimen was obtained with increasing discharge voltages.
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Quadrini, Fabrizio, Denise Bellisario, Leandro Iorio, Alice Proietti und Loredana Santo. „Additive Layer Manufacturing of Carbon Fiber/PEKK Composites for Aeronautic Application“. Materials Science Forum 1107 (06.12.2023): 9–13. http://dx.doi.org/10.4028/p-xa6tlb.
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A 3d printer has been prototyped for additive manufacturing of carbon fiber (CF) poly-ether-ketone-ketone (PEKK) composites. The machine consisted of a SCARA robot, equipped with an extrusion device. The nozzle was designed to allow the deposition of thin unidirectional (UD) tapes without affecting the fiber continuity. An elastic connection between the robot end-effector and the extruder was used for allowing tape agglomeration during manufacturing. Deposition tests were carried out at the extrusion temperature of 400°C and the rate of 130 mm/min, for a maximum number of 3 layers on a CF-epoxy laminate as substrate. The good agglomeration of the 3d printed parts and their adhesion on the composite substrate are shown by the resulted final thickness, and the ability to machine them by end milling. Results show the feasibility of using this technology for the manufacturing of composite shims in the aeronautic sector.
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Alsadon, Omar, Duncan Wood, David Patrick, Durgesh Bangalore und Sarah Pollington. „Optical properties of polyetherketoneketone based indirect dental restorations veneered with composite“. Polimery 67, Nr. 4 (13.05.2022): 141–48. http://dx.doi.org/10.14314/polimery.2022.4.1.
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In this study, the optical properties of indirect dental restorations based on poly-ether-ketone-ketone (PEKK), zirconia (YZ), and nickel-chromium (Ni-Cr) veneered with composite were compared. Based on the spectral reflectance, the CIE L*a*b* color coordinates, the color difference (ΔE), the opacity and the translucency parameter (TP) were determined using a spectrophotometer equipped with a D65 illuminant. The PEKK and Ni-Cr groups demonstrated similar CIE L*a*b* color values on white and black backgrounds. However, the zirconia group on a white backgrounds showed a slight shift in values towards red-yellow shades. The highest recorded ∆E values were 1.3 and 1.61 between PEKK and YZ groups, and Ni-Cr and YZ groups respectively. The opacity and translucency (TP) parameters were consistent with the spectral reflectance data, with the Ni-Cr and PEKK groups being completely opaque (100% and 0 TP). It has been shown that the use of the same indirect light-cured composite veneer with different substructure materials has no clinical effect on the esthetics of the final restoration.
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Lu, Wenhsuan, Conglei Li, Jian Wu, Zhongshi Ma, Yadong Zhang, Tianyi Xin, Xiaomo Liu und Si Chen. „Preparation and Characterization of a Polyetherketoneketone/Hydroxyapatite Hybrid for Dental Applications“. Journal of Functional Biomaterials 13, Nr. 4 (05.11.2022): 220. http://dx.doi.org/10.3390/jfb13040220.
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Here, we developed a new synthetic method for the production of a new class of polymeric inorganic hybrid biomaterial that has potential for dental implant applications and, in general, other orthopedic applications owing to its excellent mechanical properties and biomechanical compatibility. The new hybrid biomaterial is a composite consisting of polyetherketoneketone (PEKK) and hydroxyapatite (HA). This hybrid material boasts several unique features, including its high HA loading (up to 50 wt%), which is close to that of natural human bone; the homogeneous HA distribution in the PEKK matrix without phase separation; and the fact that the addition of HA has no effect on the molecular weight of PEKK. Nanoindentation analysis was used to investigate the mechanical properties of the composite, and its nano/microstructure variations were investigated through a structural model developed here. Through nanoindentation technology, the newly developed PEKK/HA hybrid biomaterial has an indentation modulus of 12.1 ± 2.5 GPa and a hardness of 0.42 ± 0.09 GPa, which are comparable with those of human bone. Overall, the new PEKK/HA biomaterial exhibits excellent biomechanical compatibility and shows great promise for application to dental and orthopedic devices.
Dissertationen zum Thema "PEKK composite"
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Lesimple, Gwladys. „Interaction du PEKK et des composites PEKK/FC avec l'eau et le Skydrol“. Electronic Thesis or Diss., Paris, HESAM, 2023. http://www.theses.fr/2023HESAE016.
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Alléger les avions reste une problématique majeure pour l’industrie aéronautique. Le développement de composites à matrices thermoplastiques, en remplacement des thermodurcissables, permet d’obtenir des matériaux soudables et recyclables, avec une température de service supérieure. Cette thèse s’inscrit dans le cadre du projet PSPC HAICoPAS, porté par Hexcel et Arkema, dont le but est de concevoir des nappes de composites à matrices thermoplastiques hautes performances. L’objectif de cette thèse est d’évaluer l’impact de l’eau et du Skydrol (un fluide hydraulique utilisé en aéronautique) sur les propriétés des composites PEKK/FC (polyéthercétonecétone renforcé en fibres de carbone) et d’identifier les mécanismes responsables des potentielles pertes de propriétés. Pour répondre à cette problématique, l’étude porte à la fois sur la matrice PEKK seule et sur le composite PEKK/FC. Les mécanismes de transport de l’eau dans la matrice ainsi que dans le composite sont mis en évidence par gravimétrie. Les différents paramètres de transport de l’eau sont déterminés dans une gamme de températures de 30°C à 70°C, à la fois en immersion dans l’eau et par DVS pour des humidités relatives entre 10% et 90%. La diffusion de l’eau dans le PEKK seul suit une loi de Fick tandis qu’une déviation de cette loi est observée aux temps long pour le composite PEKK/FC immergé dans l’eau. La solubilité de l’eau dans le PEKK suit une loi d’Henry. Cependant, l’absorption d’eau dans le composite, en fonction de l’humidité relative, est modélisée par une loi d’Henry couplée à une loi de puissance attribuée à un phénomène de « clustering » ayant lieu dans les micro cavités. Les propriétés mécaniques de la matrice et du composite sont peu impactées par l’eau qui induit essentiellement une plastification de la matrice et qui ne semble pas impacter l’interface fibre/matrice. L’immersion de composite PEKK/FC dans le Skydrol révèle une quantité de fluide absorbé par le composite croisé [0/90] dix fois plus importante que pour l’unidirectionnel. Ce résultat est la conséquence de cavités de taille submicronique créées dans le composite [0/90] sous la forme de décohésions à l’interface fibre/matrice. Ces décohésions sont présentes uniquement au niveau des interplis des composites d’empilements croisés (0/90, ±45° ou quasi-isotropes). Leur formation est attribuée au différentiel de retrait thermique qui existe entre les fibres de carbone et la matrice PEKK, causant un champ de contraintes résiduelles post-consolidation, lors du refroidissement. Ces endommagements, très localisés, n’impactent pas les propriétés mécaniques déterminées en ILSSLightening aircraft remains a major issue for the aeronautics industry. The development of composites with thermoplastic matrices, replacing thermosetting ones, makes it possible to obtain weldable and recyclable materials, with a higher service temperature. This thesis is part of the PSPC HAICoPAS project, led by Hexcel and Arkema, whose goal is to design high-performance thermoplastic matrix composite tapes. The objective of this thesis is to evaluate the impact of water and Skydrol (a hydraulic fluid used in aeronautics) on the properties of CF/PEKK composites (carbon fiber reinforced polyetherketoneketone) and to identify the mechanisms responsible for potential loss of property. To answer this problem, the study concerns both the PEKK matrix alone and the CF/PEKK composite. The water transport mechanisms in the matrix as well as in the composite are determined by gravimetry. The different water transport parameters are measured in a temperature range of 30°C to 70°C, both in water immersion and by DVS, for relative humidities between 10% and 90%. The diffusion of water in the PEKK alone follows a Fick's law while a deviation from this law is visible at long times for the CF/PEKK composite immersed in water. The solubility of water in PEKK follows Henry's law. However, water absorption in the composite, as a function of relative humidity, is modeled by Henry's law coupled with a power law attributed to a “clustering” phenomenon taking place in the microcavities. The mechanical properties of the matrix and of the composite are little affected by water, which essentially induces plasticization of the matrix and which does not seem to affect the fibre/matrix interface. The immersion of CF/PEKK composite in the Skydrol reveals a quantity of fluid absorbed by the crossed composite [0/90] ten times greater than for the unidirectional layup. This result is the consequence of cavities of submicronic size created in the [0/90] composite in the form of decohesions at the fibre/matrix interface. These decohesions are present only at the level of the interply of the cross-ply composites (0/90, ±45° or quasi-isotropic). Their formation is attributed to the thermal shrinkage differential that exists between the carbon fibers and the PEKK matrix, causing a post-consolidation residual stress field upon cooling. These very localized damages do not affect the resulting mechanical properties in ILSS
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Choupin, Tanguy. „Mechanical performances of PEKK thermoplastic composites linked to their processing parameters“. Thesis, Paris, ENSAM, 2017. http://www.theses.fr/2017ENAM0043/document.
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Les thermoplastiques hautes performances poly(éther-cétone-cétone) (PEKK) sont actuellement étudiés avec un grand intérêt dans l’industrie aéronautique comme matrice pour la fabrication de pièces de structure composites renforcées par des fibres de carbone. En effet, les composites thermoplastiques PEKK ont l’avantage d’être consolidables hors autoclave et ont des températures de mise en œuvre plus faibles que les composites PEEK.L’objectif de cette étude est de comprendre et prédire l’évolution des propriétés mécaniques des composites PEKK suivant le cycle thermique de mise en œuvre pour déterminer les paramètres de mise en œuvre optimaux pour la fabrication des pièces composites PEKK concernant les temps de mise en œuvre et les performances mécaniques finales.Une première partie traite de la modélisation des cinétiques de cristallisation des matrices PEKK ainsi que l’influence de la cristallinité et des morphologies cristallines sur les propriétés mécaniques des matrices PEKK. Une deuxième partie se concentre sur les modifications macromoléculaires des matrices PEKK pour des hautes températures de mise en œuvre sous air et sous azote et leurs impacts sur la cristallisation et les performances mécaniques des matrices PEKK. Enfin une dernière partie présente l’influence des fibres de carbones sur les morphologies cristallines et les cinétiques de cristallisation, la fabrication de composites PEKK unidirectionnels et tissés à ± 45° sous presse et sous autoclave et enfin l’impact de la cristallinité et des morphologies cristallines sur les performances mécaniques finales des composites PEKKPoly(ether-ketone-ketone) (PEKK) high performance thermoplastics are currently studied with a great interest by the aeronautic industry as matrix for carbon fiber reinforced structural parts. In fact, PEKK composites can be consolidated out of autoclave and they have lower processing temperatures than PEEK composites.The aim of the study was to investigate and predict the evolution of PEKK composite mechanical properties depending on the processing thermal cycle to determine the best processing parameters for PEKK composite part manufacturing regarding processing times and final mechanical performances.A first part investigates the crystallization kinetics modelling of PEKK matrices and the influence of crystallinity and crystalline morphologies on PEKK matrix mechanical properties. A second part focuses on the macromolecular modifications of PEKK matrices at high processing temperatures under air and nitrogen and their impact on PEKK matrices crystallization and mechanical properties. A last part presents the influence of carbon fibers on crystalline morphologies and crystallization kinetics, the manufacturing of unidirectional and ± 45° PEKK composites under press and autoclave and finally the impact of crystallinity and crystalline morphologies on PEKK composite mechanical properties
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Marin-Franch, Pablo. „Evaluation of PTCa/PEKK composite sensors for acoustic emission detection“. Thesis, Bangor University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247954.
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Chelaghma, Saber Ayoub. „Fonctionnalisation de composites C/PEKK pour application aérospatiale : caractérisation, modélisation et influence sur les propriétés du composite“. Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30362.
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La réduction du poids des avions est l'un des grands défis de l'industrie aérospatiale. Afin d'atteindre les objectifs ambitieux en matière de consommation de carburant et de réduction des émissions, des composites renforcés de fibres de carbone, ont été introduits sur le marché. Ces matériaux suscitent un intérêt croissant, néanmoins, ils possèdent une faible conductivité électrique, ne permettant pas de garantir une protection contre la foudre. Pour cette raison, les composites chargés de particules conductrices font l'objet d'activités de recherche en cours. L'objectif est le développement de composites multifonctionnels avec des propriétés électriques accrues. Pour l'heure, la matrice thermoplastique de référence est le PEEK mais ce polymère reste toutefois cher, et sa température d'élaboration élevée. Dans ce but, des matrices thermoplastiques, telles que le PEKK, sont à nouveau étudiées. Entre la matière première et la pièce finale, la matrice thermoplastique subit plusieurs cycles de traitement à haute température (imprégnation, consolidation, procédés d'assemblage) au cours desquelles sa capacité à cristalliser évolue sans cesse. Afin d'évaluer l'impact du procédé et des constituants du composite sur les propriétés du composite, la cristallisation a fait l'objet d'une attention particulière. Deux dispositifs expérimentaux complémentaires ont été utilisés afin de caractériser la cristallisation : une platine chauffante, permettant d'appliquer un cycle thermique et d'observer la cristallisation en microscopie optique ainsi que la calorimétrie différentielle à balayage. L'influence des fibres de carbone et des particules conductrices sur la cinétique de cristallisation a été évaluée. Une diminution des temps de cristallisation a été observée à travers l'augmentation du taux de germination. Les données recueillies ont servi à développer un modèle de cinétique de cristallisation identifié à travers une approche originale en se basant sur des données microscopiques et enthalpiques. Ce modèle permet de prédire les cinétiques de cristallisation des composites à matrice PEKK mais il ne permet pas de rendre compte de la microstructure finale engendrée. Or, cette dernière a un impact non négligeable sur les propriétés mécaniques comme cela a été prouvé à travers des essais de nano-indentation. Pour prévoir la microstructure finale, un modèle basé sur l'approche pixel coloring a été développé. L'influence des fibres de carbone a été introduite à travers la formation d'une phase transcristalline. Une bonne corrélation est constatée entre l'approche analytique, la simulation et les données expérimentales en termes de cinétique de cristallisation. Des caractérisations mécaniques et électriques ont été effectuées afin d'évaluer les performances de ces nouveaux matériaux. Sur les matériaux étudiés, la réponse mécanique n'est pas homogène comme observé sur des essais de traction suivis en stéréo-corrélation. L'étude de la santé matière montre l'existence de défauts, en particulier, à l'échelle de la microstructure. Afin de prendre en compte ces particularités, il est ainsi nécessaire de décrire plus finement la microstructure. Pour cela, la tomographie à rayons X a été utilisée afin de caractériser le composite. Les récents développements de cette technique permettent, en combinaison avec des outils de segmentation, de reconstruire une géométrie représentative du matériau. Cette géométrie est utilisée pour simuler le comportement mécanique ainsi que la cristallisation. Les simulations numériques d'un VER sont capables de prédire les propriétés d'un pli, puis celles du stratifié. Cette modélisation multi-échelle pourrait réduire le nombre et le coût des campagnes expérimentales. Ainsi, déterminer les propriétés de la structure finale en se basant sur des caractérisations et simulations à l'échelle de la microstructure est un enjeu scientifique et industriel stratégique. Ce travail constitue une contribution vers cette approcheReducing aircraft weight is one of the major challenges facing the aerospace industry. In order to achieve the ambitious goals of fuel consumption and emission reduction, carbon-fiber reinforced composites have been introduced to the market. These materials are attracting increasing interest, however, they have low electrical conductivity to ensure protection against lightning strike. For this reason, composites filled with conductive particles are the subject of ongoing research activities. The objective is the development of multifunctional composites with enhanced electrical properties. Actually, the most used thermoplastic matrix is PEEK, but this polymer remains expensive, and its processing temperature is high. For this purpose, thermoplastic matrices, such as PEKK, are again studied. Between the raw material and the final part, the thermoplastic matrix undergoes several thermal steps with high temperature exposure (impregnation, consolidation, forming and assembly processes) during which its ability to crystallize evolves continuously. In order to evaluate the impact of the process and the composite constituents on its properties, crystallization has been the subject of particular attention. Two complementary experimental devices were used to characterize the crystallization. The heating stage, allows to apply a thermal cycle and observe the crystallization in optical microscopy and differential scanning calorimetry. The influence of carbon fibers and conductive fillers on the crystallization kinetics was evaluated. A decrease in crystallization times was observed through the increase of the nucleation rate. The collected data were used to develop a kinetic model identified through an original approach based on microscopic data. This model makes it possible to predict the crystallization kinetics of PEKK composites. Nevertheless, it does not make it possible to predict the final microstructure. However, the microstructure has a significant impact on mechanical properties as it has been proven through nano-indentation tests. To predict the final microstructure, a model based on the pixel coloring approach has been developed. The influence of carbon fibers has been introduced through the formation of a transcrystalline phase. A good correlation is found between the analytical approach, the simulation and the experimental data in terms of crystallization kinetics. Mechanical and electrical characterizations were performed to evaluate the performance of these new materials. On the studied materials, the mechanical response is not homogeneous as observed on tensile tests followed in stereo-correlation. The study of matter health shows the existence of defects, in particular, at the microstructure level. In order to take this particularity into account, it is thus necessary to describe the microstructure more finely. For this, X-ray tomography was used to characterize the composite. Recent developments in this technique allow, in combination with segmentation tools, to reconstruct a representative geometry of the material. This geometry is used to simulate the mechanical behaviour as well as the crystallization. The numerical simulations of an RVE are able to calculate the properties of a ply, then those of a laminate. This multi-scale modelling could reduce the number and cost of experimental campaigns. Thus, determining the properties of the final structure based on characterizations and simulation at the microstructure scale is a strategic scientific and industrial issue. This work is a contribution towards this approach
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Pedoto, Giuseppe. „Characterization and Modelling of the Thermomechanical and Ageing Behavior of PEKK and C/PEKK Composites for Aircraft Applications at High Temperatures (above the Glass Transition Temperature) Characterization of the mechanical behavior of PEKK polymer and C/PEKK composite materials for aeronautical applications below and above the glass transition temperature“. Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2020. http://www.theses.fr/2020ESMA0011.
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La sensibilisation accrue aux questions environnementales concerne aujourd'hui les structures aéronautiques en termes d'impact environnemental et traitements de fin de vie. Dans cette optique,la possibilité de remplacer, dans les composites à matrice organique (CMO) utilisés pour des applications aéronautiques, leur matrice thermodurcissable non recyclable par une matrice thermoplastique recyclable est étudiée. En outre, les polymères thermoplastiques, tels que le PEKK, ont la possibilité d'être utilisés dans des structures plus chaudes (par exemple le pylône d'un avion), faisant l'objet de sollicitations de longue durée (fluage). Les températures de service de ces structures plus élevées que celles de la température de transition vitreuse du PEKK : il en découle, dans le matériau, une perte de propriétés due au changement d'état de solide à caoutchoutique, et éventuellement l'activation de phénomènes de cristallisation etde dégradation, qui pourraient également interagir. Ce travail vise à identifier et à modéliser ces mécanismes caractérisant le comportement du PEKK, dans ces conditions extrêmes particulières.Ceci est réalisé à partir de l'analyse des résultats des essais thermomécaniques, physico-chimiques et thermomécaniques couplés avec l’oxydation. Le modèle analytique 1-D du comportement duPEKK qui résulte de l’analyse des essais est étendu en 3-D et implémenté dans une méthode d'homogénéisation/localisation semi-analytique multi-échelle pour simuler le comportement dans mêmes conditions de composites stratifiés à matrice PEKK, en faisant varier l'orientation des plis et la séquence d'empilementThe nowadays increased awareness towards environmental issues concerns aircraft structures in terms of environmental impact and end-of-life disposal. In this optics, the possibility of replacing in the organic matrix composites (CMO) employed for aircraft applications the non-recyclable thermosetting matrix with a recyclable thermoplastic one is investigated. Moreover, thermoplastic polymers, such PEKK, have the possibility of being employed in warmer structures (e.g. the aircraft pylon), undergoing long duration solicitations (creep).The service temperatures for those structures are higher than the PEKK glass transition temperature, provoking, in the material, a loss of properties deriving from a change of state from solid to rubber, and possibly the activation of crystallization and degradation phenomena, which could also interact. This work aims to identify and model the mechanisms characterizing PEKK behavior, under the structure operative service conditions. This is achieved from the analysis of the results of thermomechanical, physical-chemical and coupled thermomechanical/oxidation tests. The resulting 1-D analytical model of the PEKK behavior, is extended in 3-D and implemented in a multi-scale semi-analytical homogenization / localization method to simulate PEKK based composites under the same conditions, varying the plies orientation and stacking sequence
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Almtteri, Nassier. „Quasi-static and dynamic behaviour of composite structures based on glass fibre reinforced PEKK“. Thesis, University of Liverpool, 2018. http://livrepository.liverpool.ac.uk/3028412/.
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The aim of this thesis is to investigate the quasi-static and impact response of the newly developed composite material and the related fibre metal laminates (FMLs) that have potential to satisfy the requirements of the new generation of aircrafts such as the damage tolerance and high service temperatures. Initially, this thesis presents the findings of a research study to develop high temperature thermoplastic composites. Here, woven S-glass fibre (GF) reinforced poly-ether-ketone-ketone (PEKK) thermoplastic prepreg materials are manufactured using a dry powder prepregging method. Prior to impact testing and modelling, the properties of the composites are evaluated by conducting a series of quasi-static tests, including tension, bending and in-plane shear, at room and elevated temperatures. Quasi-static mechanical testing has shown that the optimum weight fraction of PEKK, wf, is approximately 0.4, with the properties remaining constant or dropping slightly at higher values of wf in comparison to the optimum one. The high temperature tensile tests of GF/PEKK composites have shown that there is no obvious reduction of its tensile strength under heating up to 100 oC. The perforation resistance of the target is also peaked at wf = 0.4. As expected, the energy required to perforate the targets increases with indenter diameter. Subsequent tests show that panels impacted with partially flat indenter exhibit the highest perforation resistance among the other projectiles shapes investigated. The perforation response of the titanium- and aluminium-based FMLs, with various stacking configurations, are also investigated under quasi-static and dynamic loading rates. Initial attention is focused on assessing the effect of the laser surface treatment on the residual strength of the titanium alloy and its bonding strength with the adhesive film. The tests show that the laser parameter of 4.54 J/cm2 seems an optimum parameter which gives an excellent bonding strength between the titanium foils and the PEKK film. In contrast, these treatments do not show any significant drop in the residual tensile strength of the titanium alloy. However, there is a reduction of around 35% in both tensile strength and yield strength of the aluminium alloy produced due to the processing temperature cycle. A comparison of the quasi-static and dynamic perforation responses of the FMLs have demonstrated the rate-sensitivity of these laminates at which the perforation energy increases when the loading rates pass from the quasi-static to dynamic. After testing, the FMLs specimens are sectioned to highlight the failure modes under both test conditions. The cross-sections indicate that the impact energy on these FMLs is absorbed through (1) plastic deformation and tearing of the metals, (2) delamination between the composite plies and metal layers and (3) fibre fracture. The finite element models using ABAQUS/Explicit have been developed to predict the response of the glass fibre reinforced PEKK composites to impact by projectiles based on different diameters and shapes. The outputs of these FE models are validated against the corresponding experimental force-displacement traces and failure modes. A good agreement between the predicted and measured results, in terms of the initial stiffness, maximum force and displacement and perforation mechanisms, is obtained. The validated FE models are then used to predict the perforation resistance of the fibre metal laminates with various stacking configurations under low velocity impact loading. Here, prior to the onset of the damage, the fibre reinforced composites is modelled as an orthotropic elastic material with 2D Hashin's failure criteria. The titanium and aluminium alloys are modelled as isotropic elasto-plastic materials with strain hardening. Ductile and shear damage criteria are used to model the damage initiation of the metal layers. Again, the experimental results, including the load-displacement traces, perforation energies and failure modes are successfully predicted using the FE models developed. Furthermore, the validated models have been exploited to predict the perforation response of the FMLs under different loading conditions.
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Bessaguet, Camille. „Composite hybride à matrice polymère PEKK - Niobate de sodium - graphène ou noir de carbone, pour un amortissement vibratoire passif par transduction-dissipation locale, à finalité aéronautique et spatiale“. Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30369/document.
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L'objectif de ce travail était d'améliorer l'amortissement d'un composite thermoplastique haute performance à matrice poly(éther cétone cétone) (PEKK). Pour cela, le concept d'amortissement vibratoire passif à base de particules piézoélectriques (niobate de sodium, NaNbO3) et de particules conductrices (graphène et noir de carbone) a été étudié. Les particules piézoélectriques assurent la transduction mécanique-électrique de la vibration. Les particules conductrices dissipent par effet Joule les charges électriques générées par les particules piézoélectriques au sein de la matrice polymère. La présence de ces deux types de particules favorise la dissipation de l'énergie mécanique par le phénomène de transduction-dissipation local. Ce film amortissant a ensuite été visco-contraint entre des plis composites. Les différentes contributions à la dissipation d'énergie ont été identifiées : la viscoélasticité du polymère, le stick-slip à l'interface particules/matrice, le cisaillement induit par les fibres de carbone et la transduction-dissipation locale. Ce dernier phénomène a été mis en évidence de manière significative à travers l'étude du comportement mécanique et de la réponse dynamique des empilements composites. Après l'étape de polarisation, l'aire sous le module de cisaillement dissipatif G'' du mode de relaxation mécanique α est augmentée de 18%, l'aire des boucles d'hystérésis de 16% à 34% et les amplitudes des modes de résonance sont diminuées, jusqu'à 54% pour le 2ème modeThe aim of this work was to increase the damping in a high performance thermoplastic composite with the poly(ether ketone ketone) (PEKK) as polymer matrix. The passive vibration damping concept based on piezoelectric particles (sodium niobate, NaNbO3) and conductive particles (graphene and carbon black) was studied. Piezoelectric particles ensure the mechanic-electric transduction of the vibration. Conductive particles dissipate by Joule effect the electric charges generated by the piezoelectric particles within the polymer matrix. Presence of these two kinds of particles improves the dissipation of the mechanical energy by the local transduction-dissipation phenomena. This damping film was visco-constrained between composites plies. The different contributions of energy dissipation have been identified: the polymer viscoelasticity, the stick-slip at the particle/matrix interface, the shear induced by carbon fibers and the local transduction-dissipation. The latter phenomena has been demonstrated significantly through the study of mechanical behavior and dynamic response of the laminate composites. After the polarization step, the area under the dissipative shear modulus G'' of the mechanical relaxation mode α is increased by 18%, the hysteresis loop area from 16% to 34% and resonance mode amplitudes are decreased, up to 54% for the 2nd mode
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Alexandre, Mike Abidine. „Optimisation du comportement mécanique de composites structuraux PEKK/Fibres de carbone par ensimage oligomères de PEKK“. Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30207.
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L'objectif de cette recherche est la conception et l'analyse d'un ensimage pour composites structuraux PEKK/Fibres de carbone (FC) continues. Les oligomères de PEKK (oPEKK) ont été synthétisés en laboratoire pour définir les caractéristiques physico-chimiques permettant leur utilisation comme agent d'ensimage. A partir de ce cahier des charges, un oligomère " pilote " a pu être synthétisé afin de mener des études sur la formulation de l'ensimage. A partir d'une étude quantitative de relation structure-propriété (QSPR) et des réseaux de neurone artificiels (ANN), le développement et l'optimisation d'une formulation d'ensimage " solvantfree " ont été réalisés Le dépôt de cet ensimage a été effectué selon deux protocoles : nous avons ainsi réalisé un " ensimage laboratoire " et " ensimage sur pilote ". Les performances mécaniques des composites PEKK/FC ensimés oPEKK ont été étudiées par analyse mécanique dynamique (AMD) ; quel que soit le protocole, l'ensimage optimise les performances mécaniques de manière significative. Il est intéressant de souligner que l'" ensimage sur pilote " est plus efficace que l'" ensimage laboratoire ". Outre, l'intérêt de l'ensimage au niveau de la mise en œuvre des composites, le transfert de contraintes fibre/ matrice est optimisé ce qui se traduit par une augmentation des modules mécaniques conservatif et dissipatifThe objective of this research is to design and analyze a sizing for PEKK / continuous carbon fiber (CF) structural composites. PEKK oligomers (oPEKK) were synthesized in the laboratory to define the physicochemical characteristics allowing their use as a sizing agent. From these specifications, a "pilot" oligomer was synthesized in order to carry out studies on the sizing formulation. From a study of quantitative structure-property relationship (QSPR) and artificial neural networks (ANN), the development and optimization of a "solvent-free" sizing formulation was performed. The deposit of this sizing was achieved according to two protocols: we thus produced a "laboratory sizing" and "pilot sizing". Mechanical performances of PEKK / CF without and with oPEKK sizing composites were studied by dynamic mechanical analysis (DMA). Whatever the protocol is, the sizing optimizes the mechanical performances significantly. It is interesting to note that "pilot sizing" is more efficient than "laboratory sizing". Besides the advantage of sizing for fiber placement in composite processing, the fiber / matrix stress transfer is optimized. Then, it results in an increase of both storage and loss modulus
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Martineau, Lilian. „Mise en forme de composites carbone/PEEK dans le domaine caoutchoutique“. Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2018. http://www.theses.fr/2018EMAC0008/document.
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Les matériaux composites à matrices thermoplastiques renforcées de fibres longues sont étudiés de manière intensive pour leur introduction dans les prochaines générations de pièces structurales aéronautiques. Par ses performances thermomécaniques, l’unidirectionnel carbone/PEEK apparait comme un candidat possible, toutefois les procédés actuels de formage ne semblent pas en mesure de réaliser des pièces épaisses avec ce matériau. Ce travail de thèse a pour objectif de proposer un procédé innovant capable de réaliser des pièces composites carbone/PEEK épaisses de types cornières structurales en L ou en U. Le cœur du concept est la réalisation de l’étape de mise en forme dans le domaine caoutchoutique pour favoriser le glissement inter-plis et éviter ainsi la formation de défaut de type plissement quelle que soit l’épaisseur. Dans un premier temps, la fenêtre de processabilité adaptée à l’obtention d’une préforme a été définie en se basant sur les propriétés physiques de la matrice PEEK. La mise en application du procédé proposé, faite à partir des résultats collectés, a mis en évidence la complexité des mécanismes de déformation dans ces conditions spécifiques. Une meilleure compréhension de ces mécanismes a pu être apportée par une approche de modélisation et de simulation. Enfin, la santé matière et les performances des pièces réalisées par ce nouveau procédé ont été mesurées, la comparaison à des pièces obtenues par un procédé conventionnel de formage valide le procédé proposéThermoplastic composite materials based on long carbon fibers are extensively studied to prepare their introduction in the next generation of structural parts in aerospace industry. Because of its thermomechanical properties, unidirectional carbon/PEEK appears as a potential candidate, however the current forming processes do not appear able to manufacture thick parts with this material. The aim of my PhD thesis is to propose an innovative process to produce thick carbon/PEEK parts of L-shape and U-shape profiles. The heart of the concept is to carry out the step of deformation when the matrix is in the rubbery state to promote inter-ply sliding and thus avoiding the formation of wrinkling defect whatever the thickness. In a first step, the processing window suitable to obtain a preform was defined based on the physical properties of the PEEK matrix. The implementation of the proposed method, based on the results collected, has highlighted the complexity of the deformation mechanisms under these specific conditions. A better understanding of these mechanisms has been provided by a modeling and simulation approach. Finally, the material properties and the performance of the parts produced by this new process have been measured, the comparison with parts obtained by a conventional forming process validates the proposed process
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Smith, Sarah Ruth. „Biocompatibility and surface modifications of peek and peek/carbon fibre composites“. Thesis, University of Liverpool, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333621.
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Ko, Henry Y. S. Reconsolidation pressure effects when healing delaminated thermoplastic composite structures. [Downsview, Ont.]: Dept. of Aerospace Studies and Engineering, 1989.
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Graves, Michael J. Initiation and extent of impact damage in graphite/epoxy and graphite/PEEK composites. New York: AIAA, 1988.
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Center, Langley Research, und United States. Army Aviation Systems Command., Hrsg. Mechanical property characterization and impact resistance of selected graphite/PEEK composite materials. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1991.
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1928-, Sun C. T., und Langley Research Center, Hrsg. A constitutive model for AS4/PEEK thermoplastic composites under cyclic loading. West Lafayette, IN: Purdue University, School of Aeronautics and Astronautics, 1990.
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J, Magold N., und George C. Marshall Space Flight Center., Hrsg. Cross-sectional examination of the damage zone in impacted specimens of carbon/epoxy and carbon/peek composites. [Marshall Space Flight Center, Ala.]: National Aeronautics and Space Administration, George C. Marshall Space Flight Center, 1990.
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J, Magold N., und George C. Marshall Space Flight Center., Hrsg. Cross-sectional examination of the damage zone in impacted specimens of carbon/epoxy and carbon/peek composites. [Marshall Space Flight Center, Ala.]: National Aeronautics and Space Administration, George C. Marshall Space Flight Center, 1990.
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J, Magold N., und George C. Marshall Space Flight Center., Hrsg. Cross-sectional examination of the damage zone in impacted specimens of carbon/epoxy and carbon/peek composites. [Marshall Space Flight Center, Ala.]: National Aeronautics and Space Administration, George C. Marshall Space Flight Center, 1990.
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Georgiou, I. Dissipation of mechanical work and temperature rise in AS4/PEEK thermoplastic composite. West Lafayette, Ind: Composite Materials Laboratory, Purdue University, School of Aeronautics and Astronautics, 1990.
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Rule, D. L. Low-temperature thermal conductivity of composites: Alumina fiber/epoxy and alumina fiber/PEEK. Boulder, Colo: U.S. Dept. of Commerce, National Bureau of Standards, 1989.
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Rule, D. L. Low-temperature thermal conductivity of composites: Alumina fiber/epoxy and alumina fiber/PEEK. Boulder, Colo: U.S. Dept. of Commerce, National Bureau of Standards, 1989.
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Panin, Sergey V., Lyudmila A. Kornienko, Nguyen Duc Anh, Vladislav O. Alexenko, Dmitry G. Buslovich und Svetlana A. Bochkareva. „Three-Component Wear-Resistant PEEK-Based Composites Filled with PTFE and MoS2: Composition Optimization, Structure Homogenization, and Self-lubricating Effect“. In Springer Tracts in Mechanical Engineering, 275–99. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-60124-9_13.
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AbstractThe aim of this work was to design and optimize compositions of three-component composites based on polyetheretherketone (PEEK) with enhanced tribological and mechanical properties. Initially, two-component PEEK-based composites loaded with molybdenum disulfide (MoS2) and polytetrafluoroethylene (PTFE) were investigated. It was shown that an increase in dry friction mode tribological characteristics in metal-polymer and ceramic-polymer tribological contacts was attained by loading with lubricant fluoroplastic particles. In addition, molybdenum disulfide homogenized permolecular structure and improved matrix strength properties. After that, a methodology for identifying composition of multicomponent PEEK-based composites having prescribed properties which based on a limited amount of experimental data was proposed and implemented. It was shown that wear rate of the “PEEK + 10% PTFE + 0.5% MoS2” composite decreased by 39 times when tested on the metal counterpart, and 15 times on the ceramic one compared with neat PEEK. However, in absolute terms, wear rate of the three-component composite on the metal counterpart was 1.5 times higher than on the ceramic one. A three-fold increase in wear resistance during friction on both the metal and ceramic counterparts was achieved for the “PEEK + 10% PTFE + 0.5% MoS2” three-component composite compared with the “PEEK + 10% PTFE”. Simultaneous loading with two types of fillers slightly deteriorated the polymer composite structure compared with neat PEEK. However, wear rate was many times reduced due to facilitation of transfer film formation. For this reason, there was no microabrasive wear on both metal and ceramic counterpart surfaces.
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Liceaga, J. F., und J. J. Imaz San Miguel. „Reprocessing of Carbon Fibre/PEEK Laminates“. In Composite Structures 4, 210–17. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3457-3_16.
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Yuan, Yusheng, Jim Goodson und Rihong Fan. „HP/HT Hot-Wet Resistance of Thermoplastic PEEK and Its Composites“. In Composite Materials and Joining Technologies for Composites, Volume 7, 161–77. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-4553-1_18.
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Molyneaux, A. K., und A. R. Curtis. „Buckling and Postbuckling of Carbon Fibre PEEK Composite Panels“. In Composite Structures, 325–37. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3662-4_25.
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Lai, Y. H., M. C. Kuo, J. C. Huang und M. Chen. „Thermomechanical Properties of Nanosilica Reinforced PEEK Composites“. In Composite Materials V, 15–20. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-451-0.15.
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Nardin, M., E. M. Asloun und J. Schultz. „Physico-Chemical Interactions between Carbon Fibers and Peek“. In Controlled Interphases in Composite Materials, 285–93. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-011-7816-7_28.
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Waldorff, Erik I., Samuel Fang, Nianli Zhang, Livia Visai, Marcello Imbriani, Emanuele Magalini, Eleonora Preve et al. „PEEK Titanium Composite (PTC) for Spinal Implants“. In Orthopedic Biomaterials, 427–65. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-73664-8_16.
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Andersen, Kristian Gjerrestad, Gbanaibolou Jombo, Sikiru Oluwarotimi Ismail, Yong Kang Chen, Hom Nath Dhakal und Yu Zhang. „Damage Characterisation in Composite Laminates Using Vibro-Acoustic Technique“. In Springer Proceedings in Energy, 275–82. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-63916-7_34.
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AbstractThe need to characterise in-service damage in composite structures is increasingly becoming important as composites find higher utilisation in wind turbines, aerospace, automotive, marine, among others. This paper investigates the feasibility of simplifying the conventional acousto-ultrasonic technique set-up for quick and economic one-sided in-service inspection of composite structures. Acousto-ultrasonic technique refers to the approach of using ultrasonic transducer for local excitation while sensing the material response with an acoustic emission sensor. However, this involves transducers with several auxiliaries. The approach proposed herewith, referred to as vibro-acoustic testing, involves a low level of vibration impact excitation and acoustic emission sensing for damage characterisation. To test the robustness of this approach, first, a quasi-static test was carried out to impute low-velocity impact damage on three groups of test samples with different ply stacking sequences. Next, the vibro-acoustic testing was performed on all test samples with the acoustic emission response for the samples acquired. Using the acoustic emission test sample response for all groups, the stress wave factor was determined using the peak voltage stress wave factor method. The stress wave factor results showed an inverse correlation between the level of impact damage and stress wave factor across all the test sample groups. This corresponds with what has been reported in literature for acousto-ultrasonic technique; thus demonstrating the robustness of the proposed vibro-acoustic set-up. Structural health monitoring, impact damage, acousto-ultrasonic testing, non-destructive testing.
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Nicolais, L., A. Apicella, M. A. Del Nobile und G. Mensitieri. „Solvent Sorption Synergy in Peek“. In Durability of Polymer Based Composite Systems for Structural Applications, 99–115. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3856-7_6.
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Li, Songtao. „Graphene/Carbonized Loofah Fiber/Polyetheretherketone (PEEK) Composites“. In Hierarchically Porous Bio-Carbon Based Composites for High Electromagnetic Shielding Performance, 39–54. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-1069-2_2.
Der volle Inhalt der QuelleKonferenzberichte zum Thema "PEKK composite"
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Jia, Hongyu, und Craig A. Rogers. „The Effect of Toughened Composites on the Static Buckling Load and Buckled Position of Composite Laminated Plates“. In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-1038.
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Abstract A nonlinear analysis of the buckling and post-buckling responses of a simply supported laminated composite plate under an axial in-plane compressive load is presented. The model for symmetric cross-ply laminated composite plates made from various composite materials, such as, Graphite/Epoxy, Graphite/PEKK, Graphite/PEEK, and Kevlar/PEKK is given here. The governing equations of post-buckling composite plates with large strains are obtained by using the minimum total potential energy principle. The post-buckling behaviors of Graphite/Epoxy composite plate and toughened composite plates are studied by using this model. The critical buckling load and buckled position are determined. The stress and strain fields of the buckled composite plates are also determined. Buckling analysis is combined with failure analysis by applying Tsai-Hill theory. The effect of the toughened composites (matrix, or fibers or both) on the critical buckling load, post buckling behavior of the laminated composite plates are evaluated.
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Jia, Hongyu, und Craig A. Rogers. „The Effect of Toughened Composites on Dynamic Behaviors of Composite Laminates Under the In-Plane Dynamic Load“. In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-1053.
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Abstract In order to investigate the effect of toughened composites on the dynamic behavior of the laminated composite plates under in-plane loading, a simply supported laminated composite plate under the axial in-plane dynamic load is studied. A model for symmetric cross-ply laminated composite plate is presented here. The gorvening equations of motion are obtained by using Lagrange equations. The laminated composite plates are made from various composite materials, such as, Graphite/Epoxy, Graphite/PEKK, Graphite/PEEK, and Kevlar/PEKK. This model considers the large strain, transverse inertia, and neglects the in-plane inertia. The static critical buckling load is determined. The static part and the amplitude of dynamic part of the load are less than the static critical buckling load. Dynamic buckling of the laminated composite plates is studied for dynamic instability regions and primary responses. Linear solution for dynamic instability region is obtained. Also, the linear natural frequencies are determined for different compressive loads and materials. Nonlinear solution for primary responses is also obtained. The effects of the toughened composites on the dynamic buckling responses of the plates are evaluated.
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Marin-Franch, P. „Pyroelectric properties of the PTCa/PEKK composite transducers“. In Eighth International Conference on Dielectric Materials, Measurements and Applications. IEE, 2000. http://dx.doi.org/10.1049/cp:20000538.
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RICKS, TRENTON M., ROBERT K. GOLDBERG und J. MICHAEL PEREIRA. „HIGH-ENERGY DYNAMIC IMPACT MODELING OF AN AS4D/PEKK-FC COMPOSITE USING LS-DYNA MAT213“. In Proceedings for the American Society for Composites-Thirty Eighth Technical Conference. Destech Publications, Inc., 2023. http://dx.doi.org/10.12783/asc38/36552.
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As part of the NASA Hi-Rate Composite Aircraft Manufacturing (HiCAM) Project, multiple thermoplastic composite systems are being considered as candidates for enabling a more rapid production of composite aircraft components. Various analysis methods are being explored to evaluate their capabilities and applicability to simulating the progressive failure of thermoplastic composites. One of these approaches is based on using the MAT213 material model, a tabulated composite material model recently integrated into the commercial release of Ansys LS-DYNA. For this study, a Solvay APC AS4D/PEKK-FC unidirectional tape composite system was analyzed. A MAT213 input deck was generated for this composite utilizing data from standard composite coupon tests. A series of singleelement verification exercises were performed to evaluate the correct performance of MAT213. These model inputs were then implemented into a high energy dynamic impact (HEDI) ply-by-ply model of a flat 32-ply quasi-isotropic specimen. A tie-break contact model, implemented separately from MAT213, was used to simulate delamination between individual plies. Comparisons, including deformations, damage/delamination sizes, and penetration threshold, are made to test data for a variety of impact velocities. The results demonstrate that MAT213 is a viable option for simulating progressive failure in thermoplastic composite systems under HEDI loads.
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LE LOUËT, V. „Experimental measurement of CF/PEKK tapes heating behavior in the laser assisted automated fiber placement process“. In Material Forming. Materials Research Forum LLC, 2023. http://dx.doi.org/10.21741/9781644902479-205.
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Abstract. This work takes place within the framework of the study and control of heat transfer taking place during the heating stage of the Laser Assisted Automated Fiber Placement (AFP) process. Understanding the interaction between the composite tape and the incoming laser radiation is a cornerstone for controlling the thermal history of the laminate. Laser incidence, fibre orientation and lay-up velocity have long been identified as key factors influencing the laser absorption by the composite and its increase in temperature. For the sake of simplicity, homogenous model is often used to describe phenomena inside the composite. However, the study of the radiative behaviour of laminates and tapes has shown that absorption occurs over a volume whose size depends on the carbon fibre architecture within the polymer matrix. Investigating heat transfer at micro scale is then crucial to fully understand the thermal phenomena occurring in the AFP process. In order to investigate heat transfer according to process parameters and especially to the orientation of the tape, a specific bench is developed in order to perform static heating a single composite with a laser diode. A full calibration of the bench was first performed including the response of the IR camera as well as the shape and power imposed by the laser source. Then, measurements for several orientations of the tape (0°,45° and 90°) were performed and thermal response measured and analysed.
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Pereira, Mike, Sandi G. Miller, Duane M. Revilock, Charles R. Ruggeri und Richard E. Martin. „High Energy Dynamic Impact Testing of APC AS4D/PEKK-FC and TC1225 LMPAEK T700G Thermoplastic Composite Materials“. In AIAA SCITECH 2023 Forum. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2023. http://dx.doi.org/10.2514/6.2023-1903.
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MORRIS, KYLE S., THOMAS A. CENDER, ERIK T. THOSTENSON und SHRIDHAR YARLAGADDA. „METHODOLOGY FOR CHARACTERIZING THE FORMING LIMITS OF HIGHLY ALIGNED DISCONTINUOUS FIBER COMPOSITE LAMINATES“. In Proceedings for the American Society for Composites-Thirty Eighth Technical Conference. Destech Publications, Inc., 2023. http://dx.doi.org/10.12783/asc38/36645.
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Highly aligned discontinuous fiber (ADF) composite laminates have demonstrated potential to stretch form biaxially to complex geometry while retaining aerospace grade properties. This work utilizes Tailored Universal Feedstock for Forming (TuFF) [1], an ADF format that uses 3mm IM7 fibers and PEKK 7002 thermoplastic resin converted to unidirectional prepreg and multiaxial blanks. To lay the groundwork for the forming process-structure-property relations, a novel methodology is developed for defining the forming limits of an ADF composite lamina by constructing a forming limit diagram (FLD). The ADF-FLD defines the strain mode forming limits based on lamina fiber orientation and will be defined with respect to a broader set of failure criteria—which can be material uniformity, consolidation quality, or specific mechanical properties. To demonstrate the methodology, ADF TuFF blanks were stretch formed at various strain levels and strain modes (longitudinal and transverse plane strain). Surface strain on stretch formed samples was measured by photogrammetry. Preliminary failure criteria were established based on acceptable variability in strain measurements to reflect the uniformity of material deformation. This unique approach to defining forming limits will be used in studying material and process variables in forming ADF composites, as well as providing part geometry and forming process design requirements.
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POLNIKORN, Purith. „Basic characterization of the CF-PEKK prepreg and laminates for low temperature applications“. In Material Forming. Materials Research Forum LLC, 2024. http://dx.doi.org/10.21741/9781644903131-45.
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Abstract. This paper investigates a carbon fibre-reinforced polyetherketoneketone (CF-PEKK) thermoplastic composite used for low-temperature applications like hydrogen tank applications. The degree of crystallinity of the prepreg as received first and then consolidated after hot press has been investigated. The melting temperature and glass transition, as well as the melting enthalpy and degree of crystallinity, were also studied by DSC (differential scanning calorimetry). The fibre volume fraction and void content after consolidation have been measured by acid digestion and an optical microscopy image analysis. Thermomechanical analysis (TMA) was also used in order the coefficients of thermal expansion (CTE) to be determined. Tensile and compressive Dynamic Mechanical Analysis (DMA)test were performed. Storage modulus, loss modulus, and Tan δ relationship have thus been analysed. Multifrequency DMA experiments have been conducted in order to create the master curve thanks to the time-temperature superposition (TTS).
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GROUVE, W. J. B. „Polymer-metal interactions and their effect on tool-ply friction of C/PEKK in melt“. In Material Forming. Materials Research Forum LLC, 2024. http://dx.doi.org/10.21741/9781644903131-56.
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Abstract. Excessive friction or adhesion between tool and surface ply can lead to processing defects during thermoplastic composite manufacturing. A previous study identified a notable increase in friction or adhesion between a mild steel tool surface and C/PEKK with prolonged dwell time at elevated temperature, a phenomenon that could not be explained by our current understanding. This work presents additional friction and differential scanning calorimetry experiments to demonstrate that the increased adhesion results from polymer-metal interactions that lead to polymer degradation and metal-polymer bonding. These findings underline the importance of tool material selection in both processing and characterization of tool-ply friction.
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CUTTING, REBECCA, WADE JACKSON, PRABHAKAR RAO und BRIAN JUSTUSSON. „PROGRESSIVE DAMAGE AND FAILURE ANALYSIS OF THERMOPLASTIC COMPOSITES IN LOW VELOCITY IMPACT USING MAT299“. In Proceedings for the American Society for Composites-Thirty Eighth Technical Conference. Destech Publications, Inc., 2023. http://dx.doi.org/10.12783/asc38/36561.
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As part of NASA’s Hi-Rate Composite Aircraft Manufacturing (HiCAM) Project, state-of-the-art progressive damage and failure analysis (PDFA) tools developed for use with thermosets are being evaluated for use in modeling alternative material systems, like thermoplastics. This work presents experimental low-velocity impact data of a thermoplastic material system, AS4D/PEKK-FC, including characterization of the impact damage mechanisms as well as associated load and displacement data from testing. Following the presentation of experimental results, two simulation approaches using the PDFA tool MAT299 in the commercial off-the-shelf finite element software LS-DYNA are employed to predict damage area and forcedisplacement responses of thermoplastic panels subjected to various impact energies. The first modeling method uses solid elements with a high-density mesh and a ply-byply modeling approach similar to previously published work for thermosets. This method has the capability of capturing individual crack development, progression, and delamination on a per ply basis. The second modeling method uses TSHELL elements that have in-plane dimensions that are an order of magnitude larger than the elements used in the solid element approach and reduces the number of elements through the thickness of the laminate. This produces a lower-fidelity model with reduced run times that is incapable of monitoring every delamination plane and damage within each ply. Results from both simulation methods are compared to experiment, and limitations of the methods are discussed.
Berichte der Organisationen zum Thema "PEKK composite"
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Jeon, Chaeyoung, Sujin Kim und Ildoo Chung. Fabrication and properties of PEKK-based hybrid 3D printable dental composite resin. Peeref, Juli 2023. http://dx.doi.org/10.54985/peeref.2307p7306119.
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Kunc, Vlastimil, Vidya Kishore, Xun Chen, Christine Ajinjeru, Chad Duty und Ahmed A. Hassen. High performance poly(etherketoneketone) (PEKK) composite parts fabricated using Big Area Additive Manufacturing (BAAM) processes. Office of Scientific and Technical Information (OSTI), September 2016. http://dx.doi.org/10.2172/1343535.
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Frazier, J. L. Damage tolerance evaluation of PEEK (polyether ether ketone) composites: Final report. Office of Scientific and Technical Information (OSTI), Dezember 1988. http://dx.doi.org/10.2172/6617723.
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Todd, R. I., C. Borsa, B. Derby und M. A. M. Bourke. Analysis of neutron diffraction peak broadening caused by internal stresses in composite materials. Office of Scientific and Technical Information (OSTI), Juli 1994. http://dx.doi.org/10.2172/10162916.
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Fink, Bruce K., Roy L. McCullough, John W. Gillespie und Jr. On the Influence of Moisture on Dielectric Properties of Polyetheretherketone (PEEK) Carbon-Fiber Composites. Fort Belvoir, VA: Defense Technical Information Center, Juni 2000. http://dx.doi.org/10.21236/ada378798.
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Glover, Austin, und Dusty Brooks. Comparison of Side-on Peak Overpressure Predictions and Measurements for Type IV Composite Overwrapped Pressure Vessel Catastrophic Failure. Office of Scientific and Technical Information (OSTI), Januar 2023. http://dx.doi.org/10.2172/2004890.
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Berman, R. G., B. E. Taylor, W. J. Davis, M. Sanborn-Barrie und J B Whalen. Crustal architecture and evolution of the central Thelon tectonic zone, Nunavut: insights from Sm-Nd and O isotope analysis, U-Pb zircon geochronology, and targeted bedrock mapping. Natural Resources Canada/CMSS/Information Management, 2024. http://dx.doi.org/10.4095/332497.
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New isotopic analyses (Sm-Nd, O, and U-Pb), targeted geological mapping, and previously published whole-rock geochemical data and high-resolution aeromagnetic surveys define ten crustal domains across the central Thelon tectonic zone. In the eastern Slave Craton, granitoid rocks in the Overby Lake domain are more isotopically evolved than in the Tinney Hills domain and include tonalite dated at 2.71 Ga. The 400 km long main leucogranite belt separates most early (ca. 2.07-1.95 Ga) Thelon tectonic zone plutonic belts from the Queen Maud Block. Oxygen isotopes support its formation via melting of a sedimentary source during peak metamorphism, which coincides with three, new 1.925-1.91 Ga leucogranite ages. Modelling of Nd-Sm isotopes indicates Neoarchean crust as basement to early Thelon tectonic zone plutonic belts. Detrital zircon geochronology suggests a 2.5 Ga basement component that is not recognized in exposed crustal domains, but is compatible with the Dharwar Craton, which can be paleomagnetically reconstructed adjacent to the Slave Craton at 2.2 Ga. Two tectonic models are discussed for the evolution of the Thelon tectonic zone in the convergent margin tectonic setting indicated by the whole-rock geochemistry and mantle-like oxygen isotopic compositions of plutonic rocks. In one model, ca. 2.1 Ga extension precedes east-dipping subduction, which leads to 1.97 Ga collision of the Slave Craton with a composite Thelon tectonic zone basement-Rae Craton, upper plate. The second model proposes a ca. 2.05 Ga Slave-microcontinent (Thelon tectonic zone basement) collision, followed by a polarity flip with west-dipping subduction, leading to ca. 1.95 Ga collision of the Rae Craton.
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VanderGheynst, Jean, Michael Raviv, Jim Stapleton und Dror Minz. Effect of Combined Solarization and in Solum Compost Decomposition on Soil Health. United States Department of Agriculture, Oktober 2013. http://dx.doi.org/10.32747/2013.7594388.bard.
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In soil solarization, moist soil is covered with a transparent plastic film, resulting in passive solar heating which inactivates soil-borne pathogen/weed propagules. Although solarization is an effective alternative to soil fumigation and chemical pesticide application, it is not widely used due to its long duration, which coincides with the growing season of some crops, thereby causing a loss of income. The basis of this project was that solarization of amended soil would be utilized more widely if growers could adopt the practice without losing production. In this research we examined three factors expected to contribute to greater utilization of solarization: 1) investigation of techniques that increase soil temperature, thereby reducing the time required for solarization; 2) development and validation of predictive soil heating models to enable informed decisions regarding soil and solarization management that accommodate the crop production cycle, and 3) elucidation of the contributions of microbial activity and microbial community structure to soil heating during solarization. Laboratory studies and a field trial were performed to determine heat generation in soil amended with compost during solarization. Respiration was measured in amended soil samples prior to and following solarization as a function of soil depth. Additionally, phytotoxicity was estimated through measurement of germination and early growth of lettuce seedlings in greenhouse assays, and samples were subjected to 16S ribosomal RNA gene sequencing to characterize microbial communities. Amendment of soil with 10% (g/g) compost containing 16.9 mg CO2/g dry weight organic carbon resulted in soil temperatures that were 2oC to 4oC higher than soil alone. Approximately 85% of total organic carbon within the amended soil was exhausted during 22 days of solarization. There was no significant difference in residual respiration with soil depth down to 17.4 cm. Although freshly amended soil proved highly inhibitory to lettuce seed germination and seedling growth, phytotoxicity was not detected in solarized amended soil after 22 days of field solarization. The sequencing data obtained from field samples revealed similar microbial species richness and evenness in both solarized amended and non-amended soil. However, amendment led to enrichment of a community different from that of non-amended soil after solarization. Moreover, community structure varied by soil depth in solarized soil. Coupled with temperature data from soil during solarization, community data highlighted how thermal gradients in soil influence community structure and indicated microorganisms that may contribute to increased soil heating during solarization. Reliable predictive tools are necessary to characterize the solarization process and to minimize the opportunity cost incurred by farmers due to growing season abbreviation, however, current models do not accurately predict temperatures for soils with internal heat generation associated with the microbial breakdown of the soil amendment. To address the need for a more robust model, a first-order source term was developed to model the internal heat source during amended soil solarization. This source term was then incorporated into an existing “soil only” model and validated against data collected from amended soil field trials. The expanded model outperformed both the existing stable-soil model and a constant source term model, predicting daily peak temperatures to within 0.1°C during the critical first week of solarization. Overall the results suggest that amendment of soil with compost prior to solarization may be of value in agricultural soil disinfestations operations, however additional work is needed to determine the effects of soil type and organic matter source on efficacy. Furthermore, models can be developed to predict soil temperature during solarization, however, additional work is needed to couple heat transfer models with pathogen and weed inactivation models to better estimate solarization duration necessary for disinfestation.