Blog de veille - Matériaux composites et éolien

2 août 2021

Impression 3D/4D de matériaux composites thermoplastiques : Dossier complet | Techniques de l’Ingénieur

L’impression 3D de thermoplastiques renforcés par des fibres (discontinues et continues) permet de pallier les performances mécaniques modérées des pièces imprimées en polymère pur. Cet article présente un état des lieux de la technologie de fabrication par filament fondu (FFF) de composites, qui devrait permettre d’élargir les champs d’application (aéronautique, course au large…). Il introduit aussi l’impression 4D qui permet de développer des matériaux intelligents (capteurs, actionneurs) et d’envisager des structures architecturées actionnables sous l’action de stimuli (humidité, électricité, température, pression…).

22 juillet 2021

Performance analysis of silane grafted nanosilica and aramid fibre-reinforced epoxy composite in dynamic loading and energy application | SpringerLink

In this analysis the epoxy resin was strengthened with silane grafted aramid fibre (kevlar) and nanosilica to improve the mechanical and dynamic mechanical behaviour of a turbine blade that was developed and tested. The main goal of this research was to study the role of adding silane-treated aramid fibre and nanosilica particle in epoxy made steam turbine blade. To reduce laminar shear failure under the mechanical and thermal condition, both the nanosilica and aramid fibre were silane-treated. ....

25 mai 2021

J. Compos. Sci. | Free Full-Text | Multiscale Toughening of Composites with Carbon Nanotubes—Continuous Multiscale Reinforcement New Concept

Strengthening composite structures for advanced industries such as offshore wind generation is a real issue. Due to the huge dimensions expected for next generation wind-blades, composites based on glass fibers can no longer be used due to the lack of stiffness, whereas composites based on carbon fibers are expensive. Therefore, switching to alternative structural solutions is highly needed. This might be achieved by appropriate use of carbon nanotubes (CNTs) either as fillers of epoxy matrices, especially in inter-plies, or as fillers of epoxy glues used in structural bonding joints. As an example, trailing edges of offshore wind-blades are addressed in the current article, where monolithic bonding holds together the two structural halves and where the risk of sudden and brittle separation of edges while wind-turbines are in service is quite high. This can lead to tedious and very expensive maintenance, especially when keeping in mind the huge dimensions of new generation wind turbine blades that exceed lengths of 100 m. Bond joints and composites inter-plies of the final CNT-reinforced structures will exhibit stiffness and toughness high enough to face the severe offshore environment. In this article, multiscale Finite Element (FE) modeling is carried out to evaluate mechanical properties following the addition of CNTs. To achieve an optimal reinforcement, the effect of inclination of CNTs vs. mechanical loading axis is studied. Two innovations are suggested through this numerical study: The first consists of using homogenization in order to evaluate the effects of CNT reinforcement macroscopically. The second innovation lies in this forward-looking idea to envisage how we can benefit from CNTs in continuous fiber composites, as part of a deep theoretical rethinking of the reinforcement mechanisms operating at different scales and their triggering kinetics. The presented work is purely numerical and should be viewed as a “scenario” of structural composite materials of the future, which can be used both in the offshore industry and in other advanced industries. More broadly and through what is proposed, we humbly wish to stimulate scientific discussions about how we can better improve the performances of structural composite materials. View Full-Text

Drissi-Habti, Monssef; El Assami, Yassine; Raman, Venkadesh. 2021. "Multiscale Toughening of Composites with Carbon Nanotubes—Continuous Multiscale Reinforcement New Concept" J. Compos. Sci. 5, no. 5: 135. https://doi.org/10.3390/jcs5050135

13 mai 2021

Epoxy Composites | Wiley Online Books

(2021). Front Matter. In Epoxy Composites (eds J. Parameswaranpillai, H. Pulikkalparambil, S.M. Rangappa and S. Siengchin). https://doi.org/10.1002/9783527824083.fmatter

7 mai 2021

Eolien: la mer n’appartient pas qu’aux pêcheurs! - Challenges

La France a pris un retard considérable dans l’implantation de l’éolien marin pourtant plus efficace que l’éolien terrestre et indispensable à notre mix énergétique. Derniers opposants en date les pêcheurs. Pourtant des solutions existent pour mettre tout le monde d’accord.

5 mai 2021

Plastiques et Composites : recyclés ou biosourcés ? | Techniques de l'Ingénieur

En partenariat avec le Cetim, Techniques de l'Ingénieur vous présente : Plastiques et Composites : recyclés ou biosourcés ? Mercredi 19 Mai 2021 De 10h00 à 11h30

4 mai 2021

Continuous fibre-reinforced thermoplastic acrylic-matrix composites prepared by liquid resin infusion – A review - ScienceDirect

Increasing demand for lightweight materials is a major driving force for the steady growth of the continuous fibre-reinforced polymer composite industry. In recent years, strict global targets demanding greater environmental responsibility have led to a shift in research focus to address the end-of-life challenges posed by the use of thermoset matrices.....

Materials | Free Full-Text | Sustainable End-of-Life Management of Wind Turbine Blades: Overview of Current and Coming Solutions

Various scenarios of end-of-life management of wind turbine blades are reviewed. “Reactive” strategies, designed to deal with already available, ageing turbines, installed in the 2000s, are discussed, among them, maintenance and repair, reuse, refurbishment and recycling. The main results and challenges of “pro-active strategies”, designed to ensure recyclability of new generations of wind turbines, are discussed. Among the main directions, the wind turbine blades with thermoplastic and recyclable thermoset composite matrices, as well as wood, bamboo and natural fiber-based composites were reviewed. It is argued that repair and reuse of wind turbine blades, and extension of the blade life has currently a number of advantages over other approaches. While new recyclable materials have been tested in laboratories, or in some cases on small or medium blades, there are remaining technological challenges for their utilization in large wind turbine blades. View Full-Text

Dynamic Analysis of the Optimized Savonius Vertical Axis Wind Turbine Composite Blades | J. Sol. Energy Eng. | ASME Digital Collection

This article presents a comprehensive study of the dynamic behavior of small vertical-axis wind turbines (VAWTs) based on local fabricated Savonius VAWTs, which is suitable for countries that have a moderate wind speed. The merits of this design are cleanliness, silent, start-up under low wind speed, independent wind directions, adaptability, and ease of manufacturing. Also, this article presents an experimental validation study for the optimized Savonius VAWT....

Using laminate hybridisation (CFRP-GFRP) and shaped CFRP plies to increase plate post-buckling strain to failure under shear loading - ScienceDirect

Previous works have established the response and failure behaviour of hybrid (CFRP-GFRP) laminates when subjected to a wide range of destabilising loads. However, to date no works have quantified the influence of selective laminate shapes and hybridisation on plate post-buckling strain to failure. Thus, this paper investigates the plate collapse behaviour of a novel X-braced hybrid (CFRP-GFRP) twill woven laminate, subjected to in-plane shear loading. An experimental and numerical investigation is undertaken, including the consideration of a baseline pure CFRP laminate design.....

Observing progressive damage in carbon fiber epoxy laminate composites via 3D in-situ X-ray tomography - ScienceDirect

As the use of fiber-reinforced polymer composites grows in aerospace structures, there is an emerging need to implement damage tolerant approaches. The use of in-situ synchrotron X-ray tomography enables direct observations of progressive damage relative to the microstructural features, which are studied in a T650/5320 laminate composite with two layups via monotonic tension. Specifically, the interactions of micromechanical damage mechanisms at the notch tip were analyzed through 3D image processing as the crack grew. The analysis showed intralaminar cracking was dominant during crack initiation, delamination became prevalent during the later stages of crack progression, and fiber breakage was, in general, largely related to intralaminar cracking.

Investigation of the Ballistic Performance of GFRP Laminate under 150 m/s High-Velocity Impact: Simulation and Experiment

Hybrid Plastics and Natural Materials

A Roya, A Naskara, A Ghosha, J Adhikaria, P Sahac…

Fatigue damage growth and fatigue life of unidirectional composites - ScienceDirect

A micromechanical model is developed for the prediction of the growth rate of fatigue damage zones in unidirectional fibre composites subjected to cyclic tension-tension loading. The fatigue damage occurs by progressive fibre breaks caused by the debond crack tip stress fields of fibres that have broken in earlier load cycles. The debond crack tips are taken to advance along the broken fibres due to a cyclic slip-induced decrease in the frictional sliding shear stress acting along the debonded parts of the fibres that undergo repeated forward and reverse slip. The fatigue life is calculated as the number of load cycles for damage zones to reach a critical size where rapid composite failure can occur by longitudinal splitting cracks connecting damage zones within the specimen. A parameter study is performed to explore how the damage growth rate and fatigue life depend on microscale parameters (mechanical properties of fibre, matrix and fibre/matrix interface).

Recycling of thermosetting composites for wind blade application - ScienceDirect

It is well known that wind energy could represent a promising solution to the continuous increase of energy demand in the modern society. At the end of 2016 the European wind power amounted to 153.7 GW, distributed on 77,000 wind turbines and corresponding to the 10.4% of the electrical energy supplied. Considering the EU program to increase the renewable energy share to 27% by 2030, the key role of the wind energy in the next decade is clear. As the number of wind towers that will be dismantled in the next years will continuously increase, the development of sustainable practices to dispose of these plants at the end of their life is of utmost importance....