39 results on '"Sket, Federico"'
Search Results
2. Study of the effect of strain rate on the in-plane shear and transverse compression response of a composite ply using computational micromechanics
- Author
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Rueda-Ruiz, Mario, Herraez, Miguel, Sket, Federico, Galvez, Francisco, Gonzalez, Carlos, and Molina-Aldareguia, Jon Mikel
- Subjects
Physics - Applied Physics ,Condensed Matter - Materials Science - Abstract
The use of composite materials for structures subjected to impacts requires a deep understanding about the dynamic behaviour of the material. To this end, a physically-based computational micromechanics simulation tool has been developed to predict failure initiation in a composite ply over a wide range of strain rates. The computational micromechanics framework incorporates constitutive models for the fibre, matrix and fibre-matrix interface, which are partly calibrated with novel micromechanical testing techniques. The simulation tool was applied to two matrix-dominated deformation modes of the ply: transverse compression and in-plane shear. The comparison of simulation and experimental results at coupon level have revealed a change in failure initiation mechanism of the composite ply with strain rate, which was then corroborated through observation of the fracture surfaces on the samples.
- Published
- 2023
- Full Text
- View/download PDF
3. Damage-tolerant, laminated structural supercapacitor composites enabled by integration of carbon nanotube fibres
- Author
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Rana, Moumita, Ou, Yunfu, Meng, Chenchen, Sket, Federico, González, Carlos, and Vilatela, Juan J.
- Subjects
Condensed Matter - Materials Science ,Physics - Applied Physics - Abstract
A natural embodiment for multifunctional materials combining energy-storing capabilities and structural mechanical properties are layered structures, similar to both laminate structural composites and electrochemical energy storage devices. A structural composite with integrated electric double layer capacitive storage is produced by resin infusion of a lay up including woven glass fabric used as mechanical reinforcement, carbon nanotube non-woven fabrics as electrodes/current collectors and a polymer electrolyte. The energy-storing layer is patterned with holes, which after integration form resin plugs for mechanical interconnection between layers, similar to rivets. Finite element modelling is used to optimise rivet shape and areal density on interlaminar shear properties. Galvanostatic charge discharge tests during three point bending show no degradation of properties after large deflections or repeated load/unload cycling at 3.5 V.This mechanical tolerance is a consequence of the elimination of metallic current collectors and the effective integration of multifunctional materials, as observed by electron microscopy and X-ray computed tomography. In contrast, control samples with metallic current collectors, analogous to embedded devices, rapidly degrade upon repeated bending., Comment: 27 pages, 20 figures
- Published
- 2020
- Full Text
- View/download PDF
4. Effect of Grain Orientation and Local Strains on Void Growth and Coalescence in Titanium
- Author
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Pushkareva, Marina, Sket, Federico, Segurado, Javier, Llorca, Javier, Yandouzi, Mohammed, and Weck, Arnaud
- Subjects
Condensed Matter - Materials Science - Abstract
Ductile fracture has been extensively studied in metals with weak mechanical anisotropy such as copper and aluminum. The fracture of more anisotropic metals, especially those with a hexagonal crystal structure (e.g. titanium), remains far less understood. This paper investigates the ductile fracture process in commercially pure titanium (CP-Ti) with particular emphasis on the influence of grain orientation and local state of strain on void growth. An experimental approach was developed to directly relate the growth of a void in three dimensions to its underlying grain orientation. Grain orientation was obtained by electron back scattered diffraction on void-containing CP-Ti sheets prior to their diffusion bonding. Changes in void dimensions were measured during in-situ straining within an x-ray tomography system. The strong influence of the embedded grain orientation and that of its neighbors on void growth rate and coalescence has been experimentally quantified. Finite element crystal plasticity simulations that take into account both grain orientation and the local strain state were found to predict the experimental void growth. Grains where basal slip dominates show the largest void growth rates because they are closer to a plane strain condition that favors void growth and coalescence.
- Published
- 2019
5. Binder jet green parts microstructure: advanced quantitative analysis
- Author
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Bafaluy Ojea, Sergi, Torrents-Barrena, Jordina, Pérez-Prado, María Teresa, Muñoz Moreno, Rocío, and Sket, Federico
- Published
- 2023
- Full Text
- View/download PDF
6. Energy storage in structural composites by introducing CNT fiber/polymer electrolyte interleaves
- Author
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Senokos, Evgeny, Ou, Yunfu, Torres, Juan Jose, Sket, Federico, Gonzalez, Carlos, Marcilla, Rebeca, and Vilatela, Juan J.
- Subjects
Physics - Applied Physics - Abstract
This work presents a method to produce structural composites capable of energy storage. They are produced by integrating thin sandwich structures of CNT fiber veils and an ionic liquid-based polymer electrolyte between carbon fiber plies, followed by infusion and curing of an epoxy resin. The resulting structure behaves simultaneously as an electric double-layer capacitor and a structural composite, with flexural modulus of 60 GPa and flexural strength of 153 MPa, combined with 88 mF/g of specific capacitance and the highest power (30 W/kg) and energy (37.5 mWh/kg) densities reported so far for structural supercapacitors. In-situ electrochemical measurements during 4-point bending show that electrochemical performance is retained up to fracture, with minor changes in equivalent series resistance for interleaves under compressive stress. En route to improving interlaminar properties we produce grid-shaped interleaves that enable mechanical interconnection of plies by the stiff epoxy. Synchrotron 3D X-ray tomography analysis of the resulting hierarchical structure confirms the formation of interlaminar epoxy joints. The manuscript discusses encapsulation role of epoxy, demonstrated by charge-discharge measurements of composites immersed in water, a deleterious agent for ionic liquids. Finally, we show different architectures free of current collector and electrical insulators, in which both CNT fiber and CF act as active electrodes.
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- 2018
- Full Text
- View/download PDF
7. Thermophysical properties of porous Ti2AlC and Ti3SiC2 produced by powder metallurgy
- Author
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Tsipas, S.A., Tabares, E., Weissgaerber, Thomas, Hutsch, Thomas, Sket, Federico, and Velasco, B.
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- 2021
- Full Text
- View/download PDF
8. A Methodology to Automatically Segment 3D Ultrasonic Data Using X-ray Computed Tomography and a Convolutional Neural Network
- Author
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Caballero, Juan-Ignacio, primary, Cosarinsky, Guillermo, additional, Camacho, Jorge, additional, Menasalvas, Ernestina, additional, Gonzalo-Martin, Consuelo, additional, and Sket, Federico, additional
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- 2023
- Full Text
- View/download PDF
9. Study of the effect of strain rate on the in-plane shear and transverse compression response of a composite ply using computational micromechanics
- Author
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Rueda-Ruiz, Mario, primary, Herráez, Miguel, additional, Sket, Federico, additional, Gálvez, Francisco, additional, González, Carlos, additional, and Molina-Aldareguia, Jon M., additional
- Published
- 2023
- Full Text
- View/download PDF
10. A Methodology to Automatically Segment 3D Ultrasonic Data Using X-ray Computed Tomography and a Convolutional Neural Network
- Author
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Comunidad de Madrid, Caballero, Juan-Ignacio, Cosarinsky, Guillermo, Camacho Sosa-Días, Jorge, Menasalvas, Ernestina, Gonzalo-Martin, Consuelo, Sket, Federico, Comunidad de Madrid, Caballero, Juan-Ignacio, Cosarinsky, Guillermo, Camacho Sosa-Días, Jorge, Menasalvas, Ernestina, Gonzalo-Martin, Consuelo, and Sket, Federico
- Abstract
Ultrasonic non-destructive testing (UT) is a proficient method for detecting damage in composite materials; however, conventional manual testing procedures are time-consuming and labor-intensive. We propose a semi-automated defect segmentation methodology employing a convolutional neural network (CNN) on 3D ultrasonic data, facilitated by the fusion of X-ray computed tomography (XCT) and Phased-Array Ultrasonic Testing (PAUT) data. This approach offers the ability to develop supervised datasets for cases where UT techniques inadequately assess defects and enables the creation of models with genuine defects rather than artificially introduced ones. During the training process, we recommend processing the 3D volumes as a sequence of 2D slices derived from each technique. Our methodology was applied to segment porosity, a common defect in composite materials, for which characteristics such as void size and shape remain immeasurable via UT. Precision, recall, F1 score, and Intersection over Union (IoU) metrics were used in the evaluation. The results of the evaluation show that the following challenges have to be faced for improvement: (i) achieving accurate 3D registration, (ii) discovering suitable similar keypoints for XCT and UT data registration, (iii) differentiating ultrasonic echoes originating from porosity versus those related to noise or microstructural features (interfaces, resin pockets, fibers, etc.), and, (iv) single out defect echoes located near the edges of the component. In fact, an average F1 score of 0.66 and IoU of 0.5 were obtained.
- Published
- 2023
11. A Methodology to Automatically Segment 3D Ultrasonic Data Using X-ray Computed Tomography and a Convolutional Neural Network
- Author
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Caballero Garzón, Juan Ignacio, Cosarinsky, Guillermo, Camacho, Jorge, Menasalvas Ruiz, Ernestina, Gonzalo Martín, Consuelo, Sket, Federico, Caballero Garzón, Juan Ignacio, Cosarinsky, Guillermo, Camacho, Jorge, Menasalvas Ruiz, Ernestina, Gonzalo Martín, Consuelo, and Sket, Federico
- Abstract
Ultrasonic non-destructive testing (UT) is a proficient method for detecting damage in composite materials; however, conventional manual testing procedures are time-consuming and labor-intensive. We propose a semi-automated defect segmentation methodology employing a convolutional neural network (CNN) on 3D ultrasonic data, facilitated by the fusion of X-ray computed tomography (XCT) and Phased-Array Ultrasonic Testing (PAUT) data. This approach offers the ability to develop supervised datasets for cases where UT techniques inadequately assess defects and enables the creation of models with genuine defects rather than artificially introduced ones. During the training process, we recommend processing the 3D volumes as a sequence of 2D slices derived from each technique. Our methodology was applied to segment porosity, a common defect in composite materials, for which characteristics such as void size and shape remain immeasurable via UT. Precision, recall, F1 score, and Intersection over Union (IoU) metrics were used in the evaluation. The results of the evaluation show that the following challenges have to be faced for improvement: (i) achieving accurate 3D registration, (ii) discovering suitable similar keypoints for XCT and UT data registration, (iii) differentiating ultrasonic echoes originating from porosity versus those related to noise or microstructural features (interfaces, resin pockets, fibers, etc.), and, (iv) single out defect echoes located near the edges of the component. In fact, an average F1 score of 0.66 and IoU of 0.5 were obtained.
- Published
- 2023
12. An in situ investigation of microscopic infusion and void transport during vacuum-assisted infiltration by means of X-ray computed tomography
- Author
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Vilà, Joaquim, Sket, Federico, Wilde, Fabian, Requena, Guillermo, González, Carlos, and LLorca, Javier
- Published
- 2015
- Full Text
- View/download PDF
13. An XFEM/CZM implementation for massively parallel simulations of composites fracture
- Author
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Vigueras, Guillermo, Sket, Federico, Samaniego, Cristóbal, Wu, Ling, Noels, Ludovic, Tjahjanto, Denny, Casoni, Eva, Houzeaux, Guillaume, Makradi, Ahmed, Molina-Aldareguia, Jon M., Vázquez, Mariano, and Jérusalem, Antoine
- Published
- 2015
- Full Text
- View/download PDF
14. Influence of hybridisation on energy absorption of 3D woven composites under low-velocity impact loading. Modelling and experimental validation
- Author
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Muñoz, Raúl, primary, Seltzer, Rocío, additional, Sket, Federico, additional, González, Carlos, additional, and Llorca, Javier, additional
- Published
- 2022
- Full Text
- View/download PDF
15. Characterization of creep and creep damage by in-situ microtomography
- Author
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Borbély, András, Dzieciol, Krzysztof, Sket, Federico, Isaac, Augusta, di Michiel, Marco, Buslaps, Thomas, and Kaysser-Pyzalla, Anke R.
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- 2011
- Full Text
- View/download PDF
16. Ultrafine eutectic Ti-Fe-based alloys processed by additive manufacturing – A new candidate for high temperature applications
- Author
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Gussone, Joachim, Bugelnig, Katrin, Barriobero Vila, Pere, Da Silva, Julio Cesar, Hecht, Ulrike, Sket, Federico, Cloetens, Peter, Stark, A, Schell, N., Haubrich, Jan, Requena, Guillermo, Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, and Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials
- Subjects
Near-field synchrotron ptychographic X-ray computed tomography ,Sincrotrons ,X-ray spectroscopy ,Titanium alloys ,Ultrafine microstructures ,Eutectic Ti-Fe alloys ,High temperature deformation ,Espectroscòpia de raigs X ,Titani -- Aliatges ,Enginyeria dels materials [Àrees temàtiques de la UPC] ,High temperature laser powder bed fusion ,Synchrotrons - Abstract
The development of metals tailored to the metallurgical conditions of laser-based additive manufacturing is crucial to advance the maturity of these materials for their use in structural applications. While efforts in this regard are being carried out around the globe, the use of high strength eutectic alloys have, so far, received minor attention, although previous works showed that rapid solidification techniques can result in ultrafine microstructures with excellent mechanical performance, albeit for small sample sizes. In the present work, a eutectic Ti-32.5Fe alloy has been produced by laser powder bed fusion aiming at exploiting rapid solidification and the capability to produce bulk ultrafine microstructures provided by this processing technique. Process energy densities between 160 J/mm³ and 180 J/mm³ resulted in a dense and crack-free material with an oxygen content of ~ 0.45 wt.% in which a hierarchical microstructure is formed by µm-sized ¿-Ti4Fe2Ox dendrites embedded in an ultrafine eutectic ß-Ti/TiFe matrix. The microstructure was studied three-dimensionally using near-field synchrotron ptychographic X-ray computed tomography with an actual spatial resolution down to 39 nm to analyse the morphology of the eutectic and dendritic structures as well as to quantify their mass density, size and distribution. Inter-lamellar spacings down to ~ 30–50 nm were achieved, revealing the potential of laser-based additive manufacturing to generate microstructures smaller than those obtained by classical rapid solidification techniques for bulk materials. The alloy was deformed at 600 °C under compressive loading up to a strain of ~ 30% without damage formation, resulting in a compressive yield stress of ~ 800 MPa. This study provides a first demonstration of the feasibility to produce eutectic Ti-Fe alloys with ultrafine microstructures by laser powder bed fusion that are suitable for structural applications at elevated temperature.
- Published
- 2020
17. Ultrafine eutectic Ti-Fe-based alloys processed by additive manufacturing – A new candidate for high temperature applications
- Author
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Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials, Gussone, Joachim, Bugelnig, Katrin, Barriobero Vila, Pere, Da Silva, Julio Cesar, Hecht, Ulrike, Sket, Federico, Cloetens, Peter, Stark, A, Schell, N., Haubrich, Jan, Requena, Guillermo, Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials, Gussone, Joachim, Bugelnig, Katrin, Barriobero Vila, Pere, Da Silva, Julio Cesar, Hecht, Ulrike, Sket, Federico, Cloetens, Peter, Stark, A, Schell, N., Haubrich, Jan, and Requena, Guillermo
- Abstract
The development of metals tailored to the metallurgical conditions of laser-based additive manufacturing is crucial to advance the maturity of these materials for their use in structural applications. While efforts in this regard are being carried out around the globe, the use of high strength eutectic alloys have, so far, received minor attention, although previous works showed that rapid solidification techniques can result in ultrafine microstructures with excellent mechanical performance, albeit for small sample sizes. In the present work, a eutectic Ti-32.5Fe alloy has been produced by laser powder bed fusion aiming at exploiting rapid solidification and the capability to produce bulk ultrafine microstructures provided by this processing technique. Process energy densities between 160 J/mm³ and 180 J/mm³ resulted in a dense and crack-free material with an oxygen content of ~ 0.45 wt.% in which a hierarchical microstructure is formed by µm-sized ¿-Ti4Fe2Ox dendrites embedded in an ultrafine eutectic ß-Ti/TiFe matrix. The microstructure was studied three-dimensionally using near-field synchrotron ptychographic X-ray computed tomography with an actual spatial resolution down to 39 nm to analyse the morphology of the eutectic and dendritic structures as well as to quantify their mass density, size and distribution. Inter-lamellar spacings down to ~ 30–50 nm were achieved, revealing the potential of laser-based additive manufacturing to generate microstructures smaller than those obtained by classical rapid solidification techniques for bulk materials. The alloy was deformed at 600 °C under compressive loading up to a strain of ~ 30% without damage formation, resulting in a compressive yield stress of ~ 800 MPa. This study provides a first demonstration of the feasibility to produce eutectic Ti-Fe alloys with ultrafine microstructures by laser powder bed fusion that are suitable for structural applications at elevated temperature., Peer Reviewed, Postprint (published version)
- Published
- 2020
18. Ultrafine Fe-Fe2Ti eutectics by directed energy deposition: Insights into microstructure formation based on experimental techniques and phase field modelling
- Author
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Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials, Requena, Guillermo, Bugelnig, Katrin, Sket, Federico, Milenkovic, S, Rödler, G, Weisheit, Andreas, Gussone, Joachim, Haubrich, Jan, Barriobero Vila, Pere, Pusztai, T, Gránásy, L, Theofilatos, A, Da Silva, Julio Cesar, Hecht, Ulrike, Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials, Requena, Guillermo, Bugelnig, Katrin, Sket, Federico, Milenkovic, S, Rödler, G, Weisheit, Andreas, Gussone, Joachim, Haubrich, Jan, Barriobero Vila, Pere, Pusztai, T, Gránásy, L, Theofilatos, A, Da Silva, Julio Cesar, and Hecht, Ulrike
- Abstract
We investigated the Fe-Fe2Ti eutectic microstructure obtained by Directed Energy Deposition (DED) with a hypereutectic composition of Fe-17.6 at.% Ti. Ultrafine lamellar spacings as low as 200¿nm were achieved, features which otherwise can only be obtained in thin specimens, e.g. by suction casting. However, at interlayer boundaries (ILBs) a globular morphology of the primary Fe2Ti phase is observed with halos of the Fe phase. For the given DED conditions the crystalline structure is thus discontinuous across the ILBs. Both 2D and 3D analysis methods were used to quantify the microstructure, including high resolution synchrotron holographic X-ray computed tomography (HXCT). The generic behaviour of eutectic systems under conditions that qualitatively correspond to those of laser additive manufacturing was explored by phase-field modelling for selected nucleation scenarios and alloy compositions spanning from eutectic to hyper-eutectic. While providing valuable insights into microstructure formation, the simulations point out the need to further deepen our understanding about melting under additive manufacturing conditions in order to implement suitable nucleation and / or free growth models. The simulations also show that globular ILBs can be prevented when using exactly eutectic alloy compositions., Peer Reviewed, Postprint (author's final draft)
- Published
- 2020
19. High resolution 3D and 4D characterization of microstructure formation in novel Ti alloys for additive manufacturing
- Author
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Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials, Requena, Guillermo, Barriobero Vila, Pere, Bugelnig, Katrin, Haubrich, Jan, Gussone, Joachim, Hecht, Ulrike, Sket, Federico, Da Silva, Julio Cesar, Villanova, J, Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials, Requena, Guillermo, Barriobero Vila, Pere, Bugelnig, Katrin, Haubrich, Jan, Gussone, Joachim, Hecht, Ulrike, Sket, Federico, Da Silva, Julio Cesar, and Villanova, J
- Abstract
Peer Reviewed, Postprint (author's final draft)
- Published
- 2019
20. High Resolution 3D and 4D Characterization of Microstructure Formation in Novel Ti Alloys for Additive Manufacturing
- Author
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Requena, G., primary, Barriobero-Vila, Pere, additional, Bugelnig, Katrin, additional, Haubrich, Jan, additional, Gussone, Joachim, additional, Hecht, Ulrike, additional, Sket, Federico, additional, da Silva, Julio Cesar, additional, and Villanova, Julie, additional
- Published
- 2019
- Full Text
- View/download PDF
21. The Evolution of Internal Damage Identified by Means of X-ray Computed Tomography in Two Steels and the Ensuing Relation with Gurson’s Numerical Modelling
- Author
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Suárez, Fernando, primary, Sket, Federico, additional, Gálvez, Jaime, additional, Cendón, David, additional, Atienza, José, additional, and Molina-Aldareguia, Jon, additional
- Published
- 2019
- Full Text
- View/download PDF
22. Revealing the Effect of Local Connectivity of Rigid Phases during Deformation at High Temperature of Cast AlSi12Cu4Ni(2,3)Mg Alloys
- Author
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Bugelnig, Katrin, primary, Germann, Holger, additional, Steffens, Thomas, additional, Sket, Federico, additional, Adrien, Jérôme, additional, Maire, Eric, additional, Boller, Elodie, additional, and Requena, Guillermo, additional
- Published
- 2018
- Full Text
- View/download PDF
23. Energy storage in structural composites by introducing CNT fiber/polymer electrolyte interleaves
- Author
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Senokos, Evgeny, primary, Ou, Yunfu, additional, Torres, Juan Jose, additional, Sket, Federico, additional, González, Carlos, additional, Marcilla, Rebeca, additional, and Vilatela, Juan J., additional
- Published
- 2018
- Full Text
- View/download PDF
24. Erratum: Histological response of soda-lime glass-ceramic bactericidal rods implanted in the jaws of beagle dogs
- Author
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Moya, José S., Martínez, Arturo, López-Píriz, Roberto, Guitián, Francisco, Díaz, Luis A., Esteban-Tejeda, Leticia, Cabal, Belén, Sket, Federico, Fernández-García, Elisa, Tomsia, Antoni P., and Torrecillas, Ramón
- Subjects
Ceramics ,Multidisciplinary ,Orthognathic Surgical Procedures ,Spectrometry, X-Ray Emission ,Biocompatible Materials ,Oxides ,Prostheses and Implants ,Calcium Compounds ,Anti-Bacterial Agents ,Dogs ,Jaw ,Osseointegration ,Microscopy, Electron, Scanning ,Animals ,Sodium Hydroxide ,Erratum ,Tomography, X-Ray Computed ,Porosity - Abstract
Bacterial and fungal infections remain a major clinical challenge. Implant infections very often require complicated revision procedures that are troublesome to patients and costly to the healthcare system. Innovative approaches to tackle infections are urgently needed. We investigated the histological response of novel free P2O5 glass-ceramic rods implanted in the jaws of beagle dogs. Due to the particular percolated morphology of this glass-ceramic, the dissolution of the rods in the animal body environment and the immature bone formation during the fourth months of implantation maintained the integrity of the glass-ceramic rod. No clinical signs of inflammation took place in any of the beagle dogs during the four months of implantation. This new glass-ceramic biomaterial with inherent bactericidal and fungicidal properties can be considered as an appealing candidate for bone tissue engineering.
- Published
- 2016
25. Study of the microstructure of samples ???57.3??? pre- (M1) and post- (M2) injection by XCT
- Author
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Sket, Federico
- Subjects
Modelizaci??n poros ,Tomograf??a Computada ,Inyecci??n CO2 ,Utrillas - Abstract
IMDEA - Materiales Two samples named ???57.3??? were measured by XCT (pre- and post- CO2 injection). The acquired volumes have been delivered to CIEMAT for their evaluation. The different phases are visible in XCT experiments and the differences from the two states are going to be evaluated by CIEMAT
- Published
- 2016
26. 3D microstructure and damage accumulation in a cast AlSi12Cu5Ni2 piston alloy as a function of solution Treatment
- Author
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Bugelnig, Katrin, Sket, Federico, Germann, Holger, Steffens, Thomas, Wilde, Fabian, Boller, Elodie, and Requena, Guillermo
- Subjects
Al-Si piston alloys ,solution treatment ,Metallische Strukturen und hybride Werkstoffsysteme ,damage evolution ,3D microstructure ,synchrotron tomography - Abstract
The microstructural evolution as well as the damage mecha nisms and accumulation during RT tensile deformation of an AlSi12Cu5Ni2 piston alloy for high performance die sel truck engines are studied as a function of solution heat treatment (ST) time at 500°C. For this, interrupted in-situ synchrotron tomography experiments are combined with conventional metallography investigations. The study shows that the lower resistance to structural damage of the alloy after ST is linked to the local disintegration of the highly interconnected 3D network formed by intermetallics and Si embedded in the Al-matrix.
- Published
- 2016
27. Characterization by XCT of cements SD-1 Utrillas M1 and M2
- Author
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Sket, Federico and Revisi??n, R.Campos
- Subjects
Tomograf??a Computada ,Inyecci??n CO2 ,Utrillas - Abstract
Two samples were measured by XCT (pre- and post- CO2 injection). The acquired volumes have been provided to CIEMAT for their evaluation. The different phases are visible in XCT experiments and the differences from the two states are going to be evaluated by CIEMAT- 35.4 Sample M1 and M2
- Published
- 2016
28. Study of the microstructure of samples Utrillas-65.45 pre(M1) and post(M2) injection by XCT
- Author
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Sket, Federico and Revisi??n, R.Campos
- Subjects
Modelizaci??n poros ,Tomograf??a Computada ,Utrillas ,Inyecci??n de CO2 - Abstract
Informe T??cnico IMDEA - Materiales Two samples were measured by XCT (pre??? and post??? CO2 injection). The samples investigated weer "Utrillas???62.45m". The acquired volumes have been delivered to CIEMAT for their evaluation. The different phases are visible in XCT experiments and the differences from the two states are going to be evaluated by CIEMAT.
- Published
- 2016
29. Histological response of soda-lime glass-ceramic bactericidal rods implanted in the jaws of beagle dogs
- Author
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Universidade de Santiago de Compostela. Departamento de Cirurxía e Especialidades Médico-Cirúrxicas, Universidade de Santiago de Compostela. Departamento de Edafoloxía e Química Agrícola, Moya, José S., Martínez Insúa, Arturo, López-Píriz, Roberto, Guitián Rivera, Francisco, Díaz, Luis A., Esteban-Tejada, Leticia, Cabal, Belén, Sket, Federico, Fernández-García, Elisa, Tomsia, Antoni P., Torrecillas, Ramón, Universidade de Santiago de Compostela. Departamento de Cirurxía e Especialidades Médico-Cirúrxicas, Universidade de Santiago de Compostela. Departamento de Edafoloxía e Química Agrícola, Moya, José S., Martínez Insúa, Arturo, López-Píriz, Roberto, Guitián Rivera, Francisco, Díaz, Luis A., Esteban-Tejada, Leticia, Cabal, Belén, Sket, Federico, Fernández-García, Elisa, Tomsia, Antoni P., and Torrecillas, Ramón
- Abstract
Bacterial and fungal infections remain a major clinical challenge. Implant infections very often require complicated revision procedures that are troublesome to patients and costly to the healthcare system. Innovative approaches to tackle infections are urgently needed. We investigated the histological response of novel free P2O5 glass-ceramic rods implanted in the jaws of beagle dogs. Due to the particular percolated morphology of this glass-ceramic, the dissolution of the rods in the animal body environment and the immature bone formation during the fourth months of implantation maintained the integrity of the glass-ceramic rod. No clinical signs of inflammation took place in any of the beagle dogs during the four months of implantation. This new glass-ceramic biomaterial with inherent bactericidal and fungicidal properties can be considered as an appealing candidate for bone tissue engineering
- Published
- 2016
30. Histological response of soda-lime glass-ceramic bactericidal rods implanted in the jaws of beagle dogs
- Author
-
Ministerio de Ciencia e Innovación (España), National Institutes of Health (US), Moya, J. S., Martínez, Arturo, López-Píriz, Roberto, Guitián, Francisco, Díaz, Luis A., Esteban-Tejeda, Leticia, Cabal, Belén, Sket, Federico, Fernández-García, Elisa, Tomsia, Antoni P., Torrecillas, Ramón, Ministerio de Ciencia e Innovación (España), National Institutes of Health (US), Moya, J. S., Martínez, Arturo, López-Píriz, Roberto, Guitián, Francisco, Díaz, Luis A., Esteban-Tejeda, Leticia, Cabal, Belén, Sket, Federico, Fernández-García, Elisa, Tomsia, Antoni P., and Torrecillas, Ramón
- Abstract
Bacterial and fungal infections remain a major clinical challenge. Implant infections very often require complicated revision procedures that are troublesome to patients and costly to the healthcare system. Innovative approaches to tackle infections are urgently needed. We investigated the histological response of novel free P 2 O 5 glass-ceramic rods implanted in the jaws of beagle dogs. Due to the particular percolated morphology of this glass-ceramic, the dissolution of the rods in the animal body environment and the immature bone formation during the fourth months of implantation maintained the integrity of the glass-ceramic rod. No clinical signs of inflammation took place in any of the beagle dogs during the four months of implantation. This new glass-ceramic biomaterial with inherent bactericidal and fungicidal properties can be considered as an appealing candidate for bone tissue engineering.
- Published
- 2016
31. Histological response of soda-lime glass-ceramic bactericidal rods implanted in the jaws of beagle dogs
- Author
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Moya, José S., primary, Martínez, Arturo, additional, López-Píriz, Roberto, additional, Guitián, Francisco, additional, Díaz, Luis A., additional, Esteban-Tejeda, Leticia, additional, Cabal, Belén, additional, Sket, Federico, additional, Fernández-García, Elisa, additional, Tomsia, Antoni P., additional, and Torrecillas, Ramón, additional
- Published
- 2016
- Full Text
- View/download PDF
32. An XFEM/CZM implementation for massively parallel simulations of composites fracture
- Author
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Barcelona Supercomputing Center, Vigueras, Guillermo, Sket, Federico, Samaniego, Cristobal, Wu, Ling, Noels, Ludovic, Tjahjanto, Denny, Casoni Rero, Eva, Houzeaux, Guillaume, Makradi, Ahmed, Molina-Aldareguia, Jon M., Vázquez, Mariano, Jérusalem, Antoine, Barcelona Supercomputing Center, Vigueras, Guillermo, Sket, Federico, Samaniego, Cristobal, Wu, Ling, Noels, Ludovic, Tjahjanto, Denny, Casoni Rero, Eva, Houzeaux, Guillaume, Makradi, Ahmed, Molina-Aldareguia, Jon M., Vázquez, Mariano, and Jérusalem, Antoine
- Abstract
Because of their widely generalized use in many industries, composites are the subject of many research campaigns. More particularly, the development of both accurate and flexible numerical models able to capture their intrinsically multiscale modes of failure is still a challenge. The standard finite element method typically requires intensive remeshing to adequately capture the geometry of the cracks and high accuracy is thus often sacrificed in favor of scalability, and vice versa. In an effort to preserve both properties, we present here an extended finite element method (XFEM) for large scale composite fracture simulations. In this formulation, the standard FEM formulation is partially enriched by use of shifted Heaviside functions with special attention paid to the scalability of the scheme. This enrichment technique offers several benefits since the interpolation property of the standard shape function still holds at the nodes. Those benefits include (i) no extra boundary condition for the enrichment degree of freedom, and (ii) no need for transition/blending regions; both of which contribute to maintaining the scalability of the code. Two different cohesive zone models (CZM) are then adopted to capture the physics of the crack propagation mechanisms. At the intralaminar level, an extrinsic CZM embedded in the XFEM formulation is used. At the interlaminar level, an intrinsic CZM is adopted for predicting the failure. The overall framework is implemented in ALYA, a mechanics code specifically developed for large scale, massively parallel simulations of coupled multi-physics problems. The implementation of both intrinsic and extrinsic CZM models within the code is such that it conserves the extremely efficient scalability of ALYA while providing accurate physical simulations of computationally expensive phenomena. The strong scalability provided by the proposed implementation is demonstrated. The model is ultimately validated against a full experimental campaig, A.J., A.M., D.T., L.N. and L.W. acknowledge funding through the SIMUCOMP ERA-NET MATERA + project financed by the Fonds National de la Recherche (FNR) of Luxembourg, the Consejería de Educación y Empleo of the Comunidad de Madrid, the Walloon region (agreement no 1017232, CT-EUC 2010–10-12), and by the European Unions Seventh Framework Programme (FP7/2007–2013)., Peer Reviewed, Postprint (author's final draft)
- Published
- 2015
33. An XFEM/CZM implementation for massively parallel simulations of composites fracture
- Author
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European Commission, Comunidad de Madrid, Fonds National de la Recherche Luxembourg, Vigueras, Guillermo, Sket, Federico, Samaniego, Cristobal, Ling, Wu, Noels, Ludovic, Tjahjanto, Denny, Casoni, Eva, Houzeaux, Guillaume, Makradi, Ahmed, Molina-Aldareguia, Jon, Vazquez, Mariano, Jerusalem, Antoine, European Commission, Comunidad de Madrid, Fonds National de la Recherche Luxembourg, Vigueras, Guillermo, Sket, Federico, Samaniego, Cristobal, Ling, Wu, Noels, Ludovic, Tjahjanto, Denny, Casoni, Eva, Houzeaux, Guillaume, Makradi, Ahmed, Molina-Aldareguia, Jon, Vazquez, Mariano, and Jerusalem, Antoine
- Abstract
© 2015 Elsevier Ltd. Because of their widely generalized use in many industries, composites are the subject of many research campaigns. More particularly, the development of both accurate and flexible numerical models able to capture their intrinsically multiscale modes of failure is still a challenge. The standard finite element method typically requires intensive remeshing to adequately capture the geometry of the cracks and high accuracy is thus often sacrificed in favor of scalability, and vice versa. In an effort to preserve both properties, we present here an extended finite element method (XFEM) for large scale composite fracture simulations. In this formulation, the standard FEM formulation is partially enriched by use of shifted Heaviside functions with special attention paid to the scalability of the scheme. This enrichment technique offers several benefits since the interpolation property of the standard shape function still holds at the nodes. Those benefits include (i) no extra boundary condition for the enrichment degree of freedom, and (ii) no need for transition/blending regions; both of which contribute to maintaining the scalability of the code.Two different cohesive zone models (CZM) are then adopted to capture the physics of the crack propagation mechanisms. At the intralaminar level, an extrinsic CZM embedded in the XFEM formulation is used. At the interlaminar level, an intrinsic CZM is adopted for predicting the failure. The overall framework is implemented in ALYA, a mechanics code specifically developed for large scale, massively parallel simulations of coupled multi-physics problems. The implementation of both intrinsic and extrinsic CZM models within the code is such that it conserves the extremely efficient scalability of ALYA while providing accurate physical simulations of computationally expensive phenomena. The strong scalability provided by the proposed implementation is demonstrated. The model is ultimately validated against a full
- Published
- 2015
34. Tomographic investigation of creep and creep damage under inhomogeneous loading conditions
- Author
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Sket, Federico Iván and Maschinenbau
- Subjects
Kriechen ,Aktivierungsenergie ,Kriechschädigung ,Schädlingscharakterisierung ,Synchrotron ,ddc:620 - Abstract
In dieser Arbeit wurde die Anwendbarkeit der Mikrotomographie für Untersuchung des Kriechverhaltens und Kriechschädigung unter inhomogener Belastung beschrieben. Dazu wurde ein neues Verfahren zur Auswertung der Aktivierungsenergie des Kriechens entwickelt. Das Verfahren basiert auf "in situ" Überwachung einer einachsig beanspruchten Probe die eine lineare Temperaturverteilung entlang der Spannungsachse aufweist. Die mit der tomographischen Methode im rostfreien Stahl und Messing ermittelten Aktivierungsenergien stimmen gut mit Literaturdaten überein. Ferner wird die Verteilung der Kriechschädigung in einem mehrachsig beanspruchtem, gekerbtem Hohlzylinder aus E911-Stahl beschrieben. Die Analyse der Hohlraumverteilung zeigt die eingeschränkte Diffusion als dominierenden Mechanismus für Hohlraumswachstum. Es wird die Korrelation zwischen Verteilung der Schädigung, Spannungstriaxialität, Hauptspannung und der Von-Mises-Vergleichsspannung gesucht.
- Published
- 2010
35. Towards a deeper understanding of structural biomass recalcitrance using phase-contrast tomography
- Author
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Isaac, Augusta, primary, Barboza, Vinicius, additional, Sket, Federico, additional, D’Almeida, José, additional, Montoro, Luciano, additional, Hilger, André, additional, and Manke, Ingo, additional
- Published
- 2015
- Full Text
- View/download PDF
36. Mechanical behavior and failure micromechanisms of hybrid 3D woven composites in tension
- Author
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Muñoz, R., Martínez, V., Sket, Federico, González Martínez, Carlos Daniel, Llorca Martinez, Francisco Javier, Muñoz, R., Martínez, V., Sket, Federico, González Martínez, Carlos Daniel, and Llorca Martinez, Francisco Javier
- Abstract
The deformation and failure micromechanisms of a hybrid 3D woven composite were studied in tension. Plain and open-hole composite coupons were tested in tension until failure in the fill and warp directions, as well as fiber tows extracted from the dry fabric and impregnated with the matrix. The macroscopic evolution of damage in the composite coupons was assessed by means of periodic unloading–reloading (to obtain the elastic modulus and the residual strain), whereas the microscopic mechanism were established by means of X-ray computed microtomography. To this end, specimens were periodically removed from the mechanical testing machine and infiltrated with ZnI-containing liquid to assess the main damage modes as a function of the applied strain. The experimental observations and the predictions of an isostrain model were used to understand the key factors controlling the elastic modulus, strength and notch sensitivity of hybrid 3D woven composites in tension. It was found that the full contribution of the glass fibers to the composite strength was not employed, due to the premature fracture of the carbon fibers, but their presence increased the fracture strain and the energy dissipated during fracture. Thus, hybridization of the 3D woven composite led to a notch-insensitive behavior as demonstrated by open-hole tests
- Published
- 2014
37. Automatic quantification of matrix cracking and fiber rotation by X-ray computed tomography in shear-deformed carbon fiber-reinforced laminates
- Author
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Sket, Federico, Enfedaque Díaz, Alejandro, Alton, C., González Martínez, Carlos Daniel, Molina Aldareguía, Jon M., Llorca Martinez, Francisco Javier, Sket, Federico, Enfedaque Díaz, Alejandro, Alton, C., González Martínez, Carlos Daniel, Molina Aldareguía, Jon M., and Llorca Martinez, Francisco Javier
- Abstract
The deformation and damage mechanisms of carbon fiber-reinforced epoxy laminates deformed in shear were studied by means of X-ray computed tomography. In particular, the evolution of matrix cracking, interply delamination and fiber rotation was ascertained as a function of the applied strain. In order to provide quantitative information, an algorithm was developed to automatically determine the crack density and the fiber orientation from the tomograms. The investigation provided new insights about the complex interaction between the different damage mechanisms (i.e. matrix cracking and interply delamination) as a function of the applied strain, ply thickness and ply location within the laminate as well as quantitative data about the evolution of matrix cracking and fiber rotation during deformation
- Published
- 2014
38. Optimization of curing cycle in carbon fiber-reinforced laminates: Void distribution and mechanical properties
- Author
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Hernández, S., Sket, Federico, González Martínez, Carlos Daniel, Llorca Martinez, Francisco Javier, Hernández, S., Sket, Federico, González Martínez, Carlos Daniel, and Llorca Martinez, Francisco Javier
- Abstract
A strategy is presented to optimize out-of-autoclave processing of quasi-isotropic carbon fiber-reinforced laminates. Square panels of 4.6 mm nominal thickness with very low porosity ð6 0:2%Þ were manufactured by compression molding at low pressure (0.2 MPa) by careful design of the temperature cycle to maximize the processing window. The mechanisms of void migration during processing were ascertained by means of X-ray microtomography and the effect of ply clustering on porosity and on void shape was explained. Finally, the effect of porosity and ply clustering on the compressive strength before and after impact was studied.
- Published
- 2013
39. X-Ray Tomographic Investigation of Resin Flow in Liquid Moulding of Composite Materials
- Author
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Castro Arias, Jaime, González Martínez, Carlos Daniel, and Sket, Federico
- Subjects
Ingeniería Civil y de la Construcción - Abstract
The use of composites materials in the industry has been strengthened in the last few years. In industries where materials with good specific mechanical properties are essential, the employment of composite materials has been promoted, highlighting the aeronautical, automotive, wind power and sports industries. However, the cost-per-part is still high rendering composite materials less attractive against other material options. Hence, it is crucial to keep on looking for either more economical manufacturing methods and/or optimising the current ones. Among the possible manufacturing methods, Liquid Composite Moulding (LCM) stands out due to its low cost and simplicity. However, the manufactured parts by LCM processes do not attain the quality (often measured by the amount of porosity in the part) obtained with other more expensive methods such as autoclave processing. In LCM-manufactured parts, a relatively high porosity is caused by mechanical entrapment of air when the resin is infiltrated into the dry fabric. Published investigations have confirmed that this entrapment is the result of a competition between capillary and viscous forces, which can be quantified by the modified capillary number. However, there is still much to learn about the mechanisms of void generation and transport in the different stages of the manufacturing process. In order to improve the knowledge about resin infiltration, void entrapment and transport, curing, etc. different techniques have been applied and reported in literature. Among those, one technique that stands out is X-ray tomography due to the ability to carry out inspections nondestructively and in three dimensions (3D), thus being able to look inside the composite material. These characteristics are used in this thesis to inspect in-situ the infiltration process, providing for the first time information about the infiltration and the phenomena of void formation and transport mechanism. For this purpose an in-situ set-up was developed. The study is divided into 3 different experiments, developed according to the tomographic technique employed: high-resolution tomography, laminography and fast-tomography. First of all, the fibre-resin system is characterised in order to be able to generalise any infiltration experiment by means of the modified capillary number. Resin viscosity and surface tension were characterized by rotational viscometer and modified Wilhelmy plate method, respectively, and the contact angle between resin and fibers was measured by high-resolution X-ray Computed Tomography (XCT). The contact angle results are compared with other contact angle measurements of the same or similar system (epoxy resin and E-glass fibres). With these three properties, the calculation of the modified capillary number is only dependent on the resin velocity. To gain the most benefit of high-resolution tomography, a wicking experiment was scanned at various heights when the resin reached equilibrium conditions. The XCT images allowed for analysing and quantifying the menisci formed between fibres in 3D. The shape of these menisci is directly related to the capillary pressure exerted by the interface gas-liquid since this pressure is a function of the mean curvature of the meniscus surface. In addition, the values of capillary pressure obtained from the extracted surfaces are similar to values found in literature and calculated with the Surface Evolver software. Following this characterisation, a low and an optimal velocity injection of epoxy resin into dry fibres are inspected in-situ by means of laminography. Several scans at different mould filling stages are presented. The laminography technique permits the inspection of wider moulds in comparison to standard XCT. The resin flow front within the fabric was observed in 3D with the laminographic images, allowing the calculation of the saturation profile as a function of time, quantification of void content during the infiltration process and visualising different void transport mechanisms. Additionally, the advantages and disadvantages of this technique are described. Finally, injections at low, optimal and fast resin velocity were inspected insitu by means of fast-tomography without blurring effects. With the tomographic images, the fibre impregnation and void formation processes of the three different regimes (capillary, viscous and optimal) were observed at high spatial and temporal resolutions. Variables such as saturation and void content were quantified during the measuring time. The capacity of observing the fabric inside allows for visualising in 3D the phenomena that impacts on the evolution of the quantified variables. ----------RESUMEN---------- El uso de materiales compuestos en la industria se ha potenciado en los últimos años. Industrias donde materiales con bajo peso y buenas propiedades mecánicas son fundamentales han fomentado su utilización, destacando la industria aeronáutica, automotriz, eólica y deportiva. Sin embargo, el alto precio por pieza puede restarle competitividad frente a otras opciones. Por tanto, se debe encontrar nuevos métodos de fabricación más económicos y / u optimizar los existentes. Entre los posibles métodos de fabricación destaca Liquid Composite Moulding (LCM) debido a su reducido coste y simpleza. Sin embargo, la calidad de los productos (a menudo se mide como la cantidad de porosidad dentro de la pieza) no alcanza la de otros métodos menos económicos como la fabricación por autoclave. En piezas fabricadas por LCM, una cantidad relativamente alta de porosidad es causada por el atrapamiento mecánico del aire que se produce cuando la resina se infiltra en la fibra seca. Investigaciones realizadas han confirmado que el atrapamiento de aire se debe a una competición entre las fuerzas capilares y viscosas, cuantificada por el número capilaridad modificado. Sin embargo, todavía hay mucho que aprender de los mecanismos de generación y transporte de poros en diferentes fases del proceso de fabricación. Para mejorar el conocimiento acerca de la infiltración de resina, atrapamiento y transporte de poros, curado, etc. se han aplicado distintas técnicas en diversos trabajos científicos. Entre ellos, destaca la técnica de tomografía de rayos X por su capacidad de realizar inspecciones no destructivas y en tres dimensiones (3D), permitiendo así observar el interior del material compuesto. Estas características se utilizan en esta tesis para inspeccionar in-situ el procedimiento de infiltración, por primera vez, aportando información acerca de los mecanismos de infiltración y de formación y transporte de poros. Para este fin, se ha desarrollado equipos para mediciones in-situ. El estudio se divide en 3 experimentos desarrollados de acuerdo a la técnica tomográfica utilizada: tomografía de alta resolución, laminografía y tomografía rápida. En primer lugar, se caracteriza el sistema fibra-resina para poder generalizar los resultados de cualquier infiltración mediante el número capilar modificado. La viscosidad de la resina y la tensión superficial se caracterizaron mediante un viscosímetro rotacional y el método de la placa de Wilhelmy respectivamente. El ángulo de contacto entre resina y fibras fue medido con tomografía computarizada de rayos X (XCT) de alta resolución. Los resultados obtenidos son comparables a los encontrados en la literatura para sistemas de resina epoxy y fibra de vidrio clase E. El conocimiento de estas tres propiedades permite calcular el número capilar en función solamente de la velocidad de la resina. Para sacar el mayor partido a la tomografía de alta resolución se inspeccionó a varias alturas un experimento de wicking cuando la resina alcanzó condiciones de equilibrio. Las imágenes obtenidas con XCT permitieron analizar y cuantificar los meniscos de resina que se forman entre fibras en 3D. La forma de estos meniscos está directamente relacionada con la presión de capilaridad ejercida por la interfaz líquido-gas, puesto que esta presión es función de la curvatura media de la superficie del menisco. Además, los valores obtenidos de las superficies extraídas se comparan con valores de presión capilar encontrados en literatura y con los valores obtenidos por el software Surface Evolver, obteniendo valores semejantes. Siguiendo esta caracterización, se inspeccionó in-situ una inyección a velocidad baja y otra a óptima de resina en fibra seca mediante la técnica de laminografía. Se realizaron varios escáneres en diferentes estados de llenado del molde. La técnica de laminografía permite la medición de moldes suficientemente anchos que eviten los efectos de borde. En estas se observó en 3D el frente del fluido dentro del tejido de fibras, se calculó la saturación frente al tiempo, se cuantificó la porosidad durante el proceso de infiltración y se visualizaron diferentes mecanismos de transporte de poros. Asimismo, se describen las ventajas y desventajas que ofrece la técnica propuesta. Finalmente, usando la técnica de tomografía rápida se inspeccionaron in-situ inyecciones de resina a baja, óptima y alta velocidad sin desenfoques de movimientos gracias a su bajo tiempo de medición. Con los resultados obtenidos, se observaron con alta resolución espacial y temporal los procesos de mojado de fibra y formación de poros según el tipo de régimen (capilar, óptimo y viscoso). Además, se cuantificó la evolución de variables como la saturación o el contenido de poros durante un periodo de tiempo. Al observar el interior del tejido de fibras, se visualizaron en 3D distintos fenómenos que influyen en la evolución de las variables cuantificadas.
- Published
- 2022
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