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• Additive manufacturing of continuous fibre reinforced thermoplastic composites using fused deposition modelling: Effect of process parameters on mechanical properties

  M. Caminero, J. Chacón, P. Núñez, E. García-Plaza, I. García-Moreno, J. Reverte

  Materiales Compuestos (2022). Vol. 05 - Comunicaciones Matcomp19 (2021), (Núm. 3 - Procesos de Fabricación – Materiales Funcionales.), 91

  
  

  Abstract

  Continuous Fibre Reinforced Thermoplastic Composites (CFRTPCs) are becoming alternative materials to replace the conventional thermosetting polymers and metals due to excellent mechanical performance, recycling and potential used in lightweight structures. Fused deposition modelling (FDM) is a promising additive manufacturing technology and an alternative of conventional processes for the fabrication of CFRTPCs due to its ability to build functional parts having complex geometries. The mechanical properties of a built part depend on several process parameters. The aim of this study is to characterize the effect of build orientation, layer thickness and fibre volume content on the mechanical performance of 3D printed continuous fibre reinforced composites components manufactured by a desktop 3D printer. Tensile and three-point bending tests are carried out to determine the mechanical response of the printed specimens. SEM images of fractured surfaces are evaluated to determine the effects of process parameters on failure modes. It is observed that the effect of layer thickness of nylon samples on the mechanical performance is marginally significant. In addition, continuous fibre reinforced samples show higher strength and stiffness values than unreinforced ones. The results show that carbon fibre reinforced composites exhibit the best mechanical performance with higher stiffness and flat samples exhibit higher values of strength and stiffness than on-edge samples. Additionally, the results show that strength and stiffness increase as fibre volume content increases in most cases but, conversely, the level of increment in mechanical performance is moderate with continued rise in fibre content, particularly in the case of Kevlar® and glass fibres, due to weak bonding between the fibre/nylon layers as well as the presence of increased levels of defects.

  Abstract
  Continuous Fibre Reinforced Thermoplastic Composites (CFRTPCs) are becoming alternative materials to replace the conventional thermosetting polymers and metals due to excellent [...]

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• Monitoring of Freeze-Thaw Cycles in concrete using an embedded micro-Sensor and Strain gauges

  M. Hernández, S. Aparicio, A. Zhukov, R. Varga, J. Anaya, J. Oliveraa

  Materiales Compuestos (2022). Vol. 05 - Comunicaciones Matcomp19 (2021), (Núm. 3 - Procesos de Fabricación – Materiales Funcionales.), 90

  
  

  Abstract

  This paper deals with the study of internal stress produced during freeze-thaw (F-T) cycles using two non-destructive measurement approaches: the first approach devoted to continuous and internal monitoring using an embedded sensor based on amorphous ferromagnetic microwire during the cycles, and the second one, measuring the strain variations at the surface of the specimens by means of strain gauges. Also, measurements of ultrasonic pulse velocity through the concrete specimens were taken simultaneously during the freeze-thaw cycles. The objectives of this paper are to investigate the internal strain of freeze-thaw exposure providing a new way of measurement. These inspections may provide great reference for further research on the development of a calculation modelling of deterioration process in concrete structures under a freeze-thaw environment.

  Abstract
  This paper deals with the study of internal stress produced during freeze-thaw (F-T) cycles using two non-destructive measurement approaches: the first approach devoted to [...]

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• Study of acelerated agening under concentrated solar radiation of silicon oxycarbide glases as high temperature solar receivers

  M. Mazo, I. Padilla, A. Tamayo, A. López-Delgado, J. Rubio

  Materiales Compuestos (2022). Vol. 05 - Comunicaciones Matcomp19 (2021), (Núm. 3 - Procesos de Fabricación – Materiales Funcionales.), 89

  
  

  Abstract

  Solar energy and especially concentrated solar power systems (CSP) need materials that can tolerate the demanding working conditions. In this sense, the receivers are exposed to large fluxes of solar radiation  that produce very high temperatures. In addition, due to the operational conditions of receivers large temperature variations occur during day and night, or on cloudy days being these the main aging factors. However, other factors such as humidity, salines environments or pollutans in industrial zones can not be ruled out. Silicon oxycarbide glasses (SiOC) are composite materials formed by a SiOC glass phase (matrix phase) and a C phase (reinforcing phase) homogeneously dispersed and they can be very promising candidates for this type of applications due to their excellent intrinsic properties like their high resistante against to both oxidation and very aggressive environments, good mechanical properties, etc. In this work we have focused in the evaluation of the composite materials (SiOC porous and dense) against thermal shock produced by Frenel lens that concentrated solar radiation more than 2600 times. In every cycle materials they have been heated (32 ºC s-1) an cooled (27 ºC s-1) at very high rates from room temperature to 1000 ºC. This process has been repeated 100 times or lesser in the case of catastrophic material damage. The evolution of material surface during thermal shock cycles has been followed by several techniques such confocal and electronic microscopies and Raman, Infrarred and UV-Visible spectroscopies. Porous silicon oxycarbide materials experiencied a rapid and severe degradation during the first cycles but dense one tolerates quite well the exposure againts concentrated solar radiation.

  Abstract
  Solar energy and especially concentrated solar power systems (CSP) need materials that can tolerate the demanding working conditions. In this sense, the receivers are exposed [...]

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• Laminados aeronáuticos multifuncionales y multiesclares con diferentes contenidos en grafeno obtenido por un proceso mecano-químico

  V. García-Martínez, M. Gude, M. Martínez-Miranda, S. Blanco, P. Merino, C. Merino, T. Blanco

  Materiales Compuestos (2022). Vol. 05 - Comunicaciones Matcomp19 (2021), (Núm. 3 - Procesos de Fabricación – Materiales Funcionales.), 88

  
  

  Abstract

  Este trabajo presenta los resultados obtenidos en la caracterización de laminados de material compuesto epoxi/fibra de carbono que presentan dos peculiaridades: se ha utilizado un tejido de fibra de carbono con formato non-crimp fabric (NCF) y se ha dopado la resina con diferentes contenidos de grafeno obtenidos mediante un proceso mecano-químico a partir de nanofibras de carbono. Debido a la utilización de grafeno de pequeño tamaño lateral se espera evitar el efecto de filtrado durante la fabricación de laminados mediante RTM. Los paneles fabricados presentan baja porosidad y en el caso del panel con un 0,2 % de grafeno en la resina se ha obtenido una distribución homogénea de resina y fibra en diferentes zonas a lo largo del recorrido de la resina por el panel durante la inyección. Los resultados obtenidos en el estudio de curado revelan un ligero adelanto en la reacción de curado de la resina epoxi utilizada causado por la presencia de las partículas de grafeno. Sin embargo, el grado de curado y la temperatura de transición vítrea de los paneles es muy similar. Con respecto a la caracterización mecánica, se ha obtenido un incremento del 9 % en la resistencia a cortadura interlaminar.

  Abstract
  Este trabajo presenta los resultados obtenidos en la caracterización de laminados de material compuesto epoxi/fibra de carbono que presentan dos peculiaridades: se [...]

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• Study of multifunctional composites of epoxy matrix with ceramic nanoparticles

  . I.Lorero, ,. Campo, S. Prolongo, . A.Ureña

  Materiales Compuestos (2022). Vol. 05 - Comunicaciones Matcomp19 (2021), (Núm. 3 - Procesos de Fabricación – Materiales Funcionales.), 87

  
  

  Abstract

  The research about multifunctional materials has gained special relevance in recent years. In this sense, properties such as hydrophobicity, due to their potential applications (water repellent surfaces, self-cleaning, anti-icing, protective against corrosion, etc.) in combination with others, such as thermal conductivity or electrical insulation, can lead to new materials and coatings suitable for use in the field of energy and electronics. The present work focuses on the development of multifunctional materials of epoxy resins with inorganic nanoparticles with hydrophobic properties and better heat transfer capacity. To achieve this goal, nano-reinforcements of zinc and titanium oxides of different sizes and morphologies have been selected to obtain hydrophobicity, in addition to boron nitride platelets to improve the thermal conductivity of the nanocomposites coating. Among the possible applications of these coatings would be their use as electrical insulators for high voltage applications, such as self-cleaning surfaces, scratch resistance, etc. The addition of hydrophobic coatings, which also achieve a remarkable mechanical and thermal stability, could lead to new designs of greater reliability and durability in their functions.

  Abstract
  The research about multifunctional materials has gained special relevance in recent years. In this sense, properties such as hydrophobicity, due to their potential applications [...]

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• Modification of carbon fibre/epoxy composites properties by the incorporation of nanoparticles functionalized electrospun PA6 veils

  C. Monteserín, M. Blanco, A. Pérez-Márquez, J. Maudes, J. Gayoso, J. Laza, N. Murillo, E. Aranzabe, J. Vilas

  Materiales Compuestos (2022). Vol. 05 - Comunicaciones Matcomp19 (2021), (Núm. 3 - Procesos de Fabricación – Materiales Funcionales.), 86

  
  

  Abstract

  Epoxy resin composites inherent brittleness and poor crack resistance make necessary some form of toughening. Recently, several types of nanoparticles are being incorporated due to their theoretical high stiffness and strength. However, the addition of tougheners to the entire matrix resin could lead to a decrease in in-plane mechanical properties and to an increased viscosity of the system, being reduced the processing ability of matrix resin. Moreover, a homogeneous dispersion of these nanoparticles is still a problem. Thermoplastic nanofibrous structures can tackle these problems. They offer a solution for the dispersion issue, since they can be readily embedded in the resin and incorporate a nanosized phase in the composite. These nanofibres also do not increase the viscosity of the resin. Moreover, due to their macro scale length, no health hazards are involved in the production and use of these nanofibres. This paper investigates the effect of electrospun nanofibrous veils made of polyamide 6 modified with TiO2 nanoparticles on the properties of a carbon fibre/epoxy composite. The nanofibres were incorporated in the carbon fibre/epoxy composite as stand-alone interlayered structure during a vacuum infusion process. The effect of positioning these veils in different composite positions has been investigated. Incorporation of polyamide nanofibers increases the stress at failure and the Young’s modulus. Furthermore, mode I tests showed a slight improvement. When TiO2 modified veils are incorporated in the composite, similar mechanical properties were obtained, but new antibacterial properties were achieved when irradiated with UV light widening the application area of these composites.

  Abstract
  Epoxy resin composites inherent brittleness and poor crack resistance make necessary some form of toughening. Recently, several types of nanoparticles are being incorporated [...]

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• Technological challenges of the injection moulding implementation for aeronautical parts

  D. Gil, M. Tourón

  Materiales Compuestos (2022). Vol. 05 - Comunicaciones Matcomp19 (2021), (Núm. 3 - Procesos de Fabricación – Materiales Funcionales.), 85

  
  

  Abstract

  The potential implementation in the aeronautical industry of the injection moulding manufacturing process with short fiber reinforced plastics was studied on different parts with low structural responsability within horizontal and vertical stabilizers thanks to the atractive recurent cost and hi-rate production widely demostrated within automotive industry. The present work shows the different activities performed in the frame of engineering and manufacturing  with the aim to assess the feseability for the aplication of the technology. These activities go from design, stress and mechanical testing, study of the different injection strategies and the implications in the mold design to evolve from conventional plastic to reinforced mateials mainly due to the high temperatures and anisotropy of the material Previous developments are included  in the project FACTORIA, funded by the Ministerio de Economía y Competitividad, by means of the Centro Tecnológico Industrial (CDTI), in the Strategic Programme CIEN 2018

  Abstract
  The potential implementation in the aeronautical industry of the injection moulding manufacturing process with short fiber reinforced plastics was studied on different parts [...]

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• Preform development of dry fabrics for manufacturing of large dimensions structural components by RTM for aeronautical industry

  M. Ariño, C. Builes, M. Rodríguez

  Materiales Compuestos (2022). Vol. 05 - Comunicaciones Matcomp19 (2021), (Núm. 3 - Procesos de Fabricación – Materiales Funcionales.), 84

  
  

  Abstract

  Resin Transfer Moulding Technology (RTM) is gaining attention on developing composite structural components for aeronautical industry, due to its high-cadence production, and as a consequence, a significant manufacturing cost reduction. This document describes the manufacturing of a composite fuselage frame oriented in dry reinforcement preform construction that, it’s one of the main factors that intervene in RTM process and has a direct influence on the component structural quality. It’s exposed the definition of an overlap strategy for dry Non-Crimp Fabric adaption on structural aeronautical components of large dimensions and implementation of such strategy for manufacture a real-scale demonstrator, exposing process time reduction base on a tooling design that facilitate the cycle time reduction. Simultaneously, it’s described a procedure to study the overlap influence at a dimensional and structural level and defects generation. Also, it’s exposed different overlap strategies for preform consolidation by commercial adhesives incorporation for fabrics and thermoplastic binders.

  Abstract
  Resin Transfer Moulding Technology (RTM) is gaining attention on developing composite structural components for aeronautical industry, due to its high-cadence production, [...]

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• Fast preforming for automotive applications through flexible and automated facilities

  X. Irastorza, . R.Mezzacasa, M. Segura, J. Acosta

  Materiales Compuestos (2022). Vol. 05 - Comunicaciones Matcomp19 (2021), (Núm. 3 - Procesos de Fabricación – Materiales Funcionales.), 83

  
  

  Abstract

  The use of polymer matrix composites and, in particular, based on carbon fiber, is awakening more and more interest in the automotive sector, due to the great weight reduction potential they offer for the lightening of vehicle structures. The case of the BMW (with the i3, i8 and 7 Series) and some other manufacturers, represent the first cases of use of "large scale production" with these materials, with a growth perspective provided by the electric vehicle. To achieve a mass implementation of these new materials it is a key factor the development of processes and equipment that allow manufacturing with very short cycle times. Preforming is the key stage where the fiber stacking takes the form of the injection mold in which it will be introduced later. This stage of the process is the one that has a greater impact on the cost of the overall process, so it is especially necessary to develop optimization and automation techniques for rapid preforming. In this context, Fagor Arrasate, with the aim of offering its customers a competitive installation, has created and led a project in which it has collaborated with Tecnalia to develop pre-forming installations for the automotive sector.. A fast preforming process based on preheating and cold stamping has been developed combined with an automatic material feeding based on a transfer system and also completed with the automation of the initial stacking and the trimming of the final preform. The capabilities of this installation have been validated for an automotive demonstrator.

  Abstract
  The use of polymer matrix composites and, in particular, based on carbon fiber, is awakening more and more interest in the automotive sector, due to the great weight reduction [...]

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• Use of tough matrices to improve the adhesive bonding between carbon fiber laminate layers

  M. Martínez, J. Abenojar, J. Butenegro, S. Armentia

  Materiales Compuestos (2022). Vol. 05 - Comunicaciones Matcomp19 (2021), (Núm. 3 - Procesos de Fabricación – Materiales Funcionales.), 80

  
  

  Abstract

  In recent years, the use of carbon fiber reinforced epoxi (CFRP) for the automotive industry has taken a great deal of development; whether in the manufacture of bodyworks, chassis or in interior parts with low mechanical responsibility. These structures in their normal life, will be continually subjected to external exertions of small intensity. These efforts will be able to lead to fractures in the matrix of the composite material if it presents high stiffness. For this reason, the aim of this work is to replace epoxy matrices, which are usually used to manufacture CFRP by another with large toughness like modified acrylics or epoxies. In this work, characteristics of two epoxies are compared, one of them traditionally used for high modulus composites with low deformation capacity and another that has large toughness. For that purpose, thermal and mechanical properties of the composites manufactured with them are determined.

  Abstract
  In recent years, the use of carbon fiber reinforced epoxi (CFRP) for the automotive industry has taken a great deal of development; whether in the manufacture of bodyworks, [...]

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