The increasing use of carbon fibre reinforced polymers (CFRPs) in aircraft introduces significant end-of-life (EOL) challenges, as these high-value and high embedded-energy materials frequently face disposal. This study explores reusing EOL aircraft CFRP components for strengthening reinforced concrete (RC) structures, promoting cross-sectoral circularity. The proposed segmentation strategies for fuselage and wing stiffeners were applied to fragments from a decommissioned Airbus A350 fuselage section. Although the reclaimed laminates exhibit lower stiffness and strength than common commercial unidirectional strips used to strengthen concrete, equivalent structural performance can be achieved by increasing the reinforcement cross-section. Experimental tests on RC beams strengthened with composite fragments from a decommissioned aircraft section showed that reused laminates enhanced the flexural response by delaying crack initiation and steel yielding and by increasing load capacity by 123.7%, with favourable bond performance. Moreover, reusing EOL laminates requires far less energy (roughly 400 times lower) than producing virgin or recycled CFRPs, making it a highly sustainable option. Findings confirm structural reuse as a technically viable and highly sustainable alternative for aerospace CFRP waste, linking aircraft decommissioning with civil infrastructure rehabilitation. Based on this initial validation, a more systematic investigation of the parameters governing bond behaviour and flexural performance is necessary before the results can be generalised.

Nowadays, the disposal of wind turbine blades (WTB) represents a significant challenge due to their complex construction and massive size. The reuse of decommissioned WTB in the construction sector has emerged as a promising solution that can reduce waste and create a circular economy for the valuable materials contained therein. This paper studies the possibility to reuse the main structural components of a WTB as roof beam for a multisport pavilion. The approach relies on reusing the main load carrying component of the blade (i.e., the spar caps plus shear webs) as an overhanging beam, with the thinner part of the blade cantilevered. A structural analysis was carried out using a detailed numerical model considering a WTB from the Siemens Gamesa G90–2.0 MW wind turbine, with a total blade length of 44 m. The model takes into account the actual cross section geometry along the blade length as well as the material properties and the stacking sequence of the laminates. The commercial finite element software ABAQUS is used to accurately predict the stress and deformation distribution of the blade structure acting as an overhanging beam. The preliminary results of this study show potential suitability for the WTB to be reused as beams in roof structures considering bending stresses.

Local overheating during curing of thermosetting resins is likely to occur for thick laminates or during fast curing. Overheating may lead to heterogeneous mechanical properties along the laminate thickness or even to an uncontrolled reaction. To avoid overheating, most thermoset resin manufacturers recommend a "safe" cure cycle. However, these cure cycles can be improved to shorten cure times in thin laminates and may not be good enough to avoid overheating in thick laminates. In this paper, we propose a new analytical model to determine the critical thickness above which thermal runaway occurs when the laminate is heated at a constant rate up to a constant temperature. The model considers different thermal boundaries between the mould and the laminate, i.e., from a perfect thermal contact to a contact of infinite resistance. The analytical model was corroborated through the numerical integration of the equations governing it and experimental data from the curing process of a thick laminate composed of the commercial VTC401 epoxy resin and M55J carbon fiber system. Model predictions indicate that, under the manufacturer’s recommended cure cycle, which includes an initial heating rate of 2 K/min, thermal runaway occurs in laminates thicker than 12.4 mm, aligning with experimental observations. A 20-mm-thick laminate, exceeding this threshold, was cured using a reduced heating rate of 0.3 K/min based on our criteria, successfully preventing overheating. The maximum temperature gradient recorded experimentally remained below 1°C, confirming the model's prediction of uniform thermalization.

Single-Step Punch Interlocking (SSPI) is a recently developed joining methodology between aluminium and Carbon Fibre Reinforced Polymer (CFRP) aiming to contribute to multi-material design of structural parts. This hybrid joint technology combines adhesive bonding with mechanical interlocking. Elucidating the failure mechanism of the developed joint is relevant to provide insights for future enhancements in performance, increase its lifespan and prevent premature failure. Therefore, the different subcritical failure events were identified through interrupted Single-Lap Shear (SLS) tests and subsequent nondestructive ultrasonic inspection, and the global failure mechanism was described. Results indicate that the addition of the SSPI joint delayed the onset and propagation of adhesive failure between both substrates, providing residual strength and increasing the ultimate load in a 65 % and the absorbed energy of the joint in a 156 %. (c) 2025 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

There is a lack of knowledge concerning the interlaminar fracture toughness under mixed-mode ratios of 3D-printed composites. In this work, several additive manufacturing (AM) continuous Fiber Reinforced Thermoplastic (cFRT) specimens have been tested to characterize the initiation and propagation of interlaminar fracture toughness under three different mixed-mode GII/(GI + GII) ratios: 25, 50, and 75%. The results obtained do not exhibit the common tendency seen in traditional laminated composite materials, in which the fracture toughness increases with the mixed-mode ratio. While the fracture toughness for the 50% mixed-mode ratio falls between the corresponding mode I and mode II values, the fracture toughness for the 25% and 75% ratios falls outside this range. To provide a reasonable explanation, fractography and microstructure analyses were conducted to quantify fiber, matrix, and void contents. It was concluded that this uncommon behavior is probably related to the intrinsic variability of the material and manufacturing process.Highlights Continuous fibers improve mechanical properties of 3D-printed composite parts. Delamination is a critical failure mode for laminated composite materials. Characterization of mixed-mode delamination is key for simulation and design. First complete study of mixed-mode delamination for 3D-printed composites.

The understanding of the impact behaviour of additive manufactured continuous fibre reinforced polymers must start from the analysis of the damage mechanisms. In this investigation, the impact damage in a 3Dprinted continuous carbon fibre reinforced polymer is studied by means of quasi -static indentation tests. The coupons are manufactured with Fused Filament Fabrication (FFF) using a thermoplastic resin. Three indentation displacement levels were tested, analysing different phases of the impact using X-ray Computed Tomography. The effects of fibre orientation were considered, establishing a comparison between one laminate with conventional orientations (0, 90, +/- 45) and one with disperse orientations. Results show a progressive damage generation influenced by the inherent defects of the manufacturing process, characterized by delamination growth and stiffness reduction. Fibre and matrix breakage only appear at the final stages when the laminate peak load is reached. The considered dispersed laminate shows less delaminated interfaces compared to the conventional one.

Because long curing times hinder the mass manufacturing of composite products, there is a constant quest to develop shorter curing cycles that maintain material quality. The authors recently developed a curing prediction methodology for thermoset composites based on an isoconversional model, which is used in this work to shorten the curing time of real practice processes. The investigation presents two optimized cure cycles devised to reduce the curing times recommended by the resin manufacturer while assure a complete degree of cure and restricting the exothermal flow to avoid undesired overheating. The mechanical (compression, in-plane, and interlaminar shear) and physical ( T_g , void content, and outgassing) properties of specimens extracted from panels manufactured according to recommended curing cycles and the two time-reduced cycles (up to 72

The loading-rate mechanical response of the mode I delamination in composites and adhesively bonded joints was investigated. The tests were carried out using a recently developed Guided Double Cantilever Beam test method. Three different data reduction methods were proposed and assessed: a displacement-based formulation, a near-crack-tip displacement formulation, and a numerical assessment using the Virtual Crack-Closure Technique method. The methods account for the dynamic effects which may be present. While small differences between the three different methods can be seen, no rate-dependency higher than the uncertainty for the materials and the loading rates considered have been evidenced.

It is well known that the use of continuous reinforcing fibers can largely improve the typical low in-plane mechanical properties of 3D-printed parts. However, there is very limited research on the characterization of the interlaminar fracture toughness of 3D-printed composites. In this study, we investigated the feasibility of determining the mode I interlaminar fracture toughness of 3D-printed cFRP composites with multidirectional interfaces. First, elastic calculations and different FE simulations of Double Cantilever Beam (DCB) specimens (using cohesive elements for the delamination, in addition to an intralaminar ply failure criterion) were carried out to choose the best interface orientations and laminate configurations. The objective was to ensure a smooth and stable propagation of the interlaminar crack, while preventing asymmetrical delamination growth and plane migration, also known as crack jumping. Then, the best three specimen configurations were manufactured and tested experimentally to validate the simulation methodology. The experimental results confirmed that, with the appropriate stacking sequence for the specimen arms, it is possible to characterize the interlaminar fracture toughness in multidirectional 3D-printed composites under mode I. The experimental results also show that both initiation and propagation values of the mode I fracture toughness depend on the interface angles, although a clear tendency could not be established.

Although the rate-dependent behaviour of the interlaminar fracture toughness of fibre reinforced composites has been a matter of ongoing research in recent decades, further research is required into characterising these properties and, consequently, developing more reliable constitutive models to simulate dynamic events. Furthermore, despite the various studies that have been carried out, no consensus on which test method to use to characterise these properties has yet been reached. This paper presents a new test method for measuring the dynamic mode I interlaminar fracture toughness in composite laminates by using a novel device based on a modified Double Cantilever Beam test method with a guided tensile configuration. In contrast to other methods reported in the literature, the proposed device guarantees a symmetric crack opening and, thus, pure mode I propagation during high loading rate testing. When used in a dynamic servo-hydraulic testing machine with controllable displacement rate, a constant opening velocity can be achieved. The Guided Double Cantilever Beam testing method is validated against a quasi-static Double Cantilever Beam test, showing good agreement between the results. The testing method has been satisfactorily tested under intermediate/high loading rates, from 0.1 to 10 m/s.

The mass manufacturing of composite products is hindered by long curing times, and composite manufacturers demand shorter curing cycles while keeping material properties. This requires reliable methods to predict the curing kinetics of each resin formulation. Isoconversional methods are easy to implement and able to deal with complex processes. However, scientists still limit their isoconversional predictions of curing degree to isothermal or constant heating programs. In this study, we perform combined dynamic and isothermal DSC measurements for two different commercial epoxies for aerospace applications (M18 and VTC401). Based on the isoconversional kinetic analysis, we show the feasibility of predicting the evolution of an epoxy resin cure for an arbitrary and complex temperature program using two different unexplored methods for this purpose. Because of the versatility of both prediction methods, they are especially suited to deal with actual conditions in industrial processes. The proposed approach is validated experimentally by comparing predictions against the curing degree of these epoxies during a temperature program that comprises isothermal and dynamic stages. These reliable and straightforward predictions open the door to optimize curing times and increase productivity in composites.

In the mass production of composite materials, an unrealistic interpretation of specific parameters such as raw material consumption or cycle time per process may be counterproductive to business performance. This study proposes integrating a lean tool (Value Stream Map) into a DMAIC-based approach to improve process performance in composite padel racket manufacturing. The system presented is particularly useful in mass production as it is a customer-driven approach that aims to reduce waste (both material and time) and variation, thereby enhancing the quality of end-use composite products and their common manufacturing processes (cutting, laminating, and curing). The proposed procedure's effectiveness in improving CoFRP processing within the sporting goods industry is noteworthy as cost savings and process performance have been increased by 18.5% and 15%, respectively, in workstations where advanced composite materials are processed.

The use of continuous fiber as reinforcement in polymer additive manufacturing technologies enhances the mechanical performance of the manufactured parts. This is the case of the Carbon-Fiber reinforced PolyAmide (CF/PA) used by the MarkForged MarkTwo® 3D printer. However, the information available on the mechanical properties of this material is limited and with large variability. In this work, the in-plane mechanical properties and the interlaminar fracture toughness in modes I and II of Markforged’s CF/PA are experimentally investigated. Two different standard specimens and end-tabs are considered for the in-plane properties. Monolithic CF/PA specimens without any additional reinforcement are used for the interlaminar fracture toughness characterization. Two different mode I specimen configurations are compared, and two different test types are considered for mode II. The results show that prismatic specimens with paper end-tabs are more appropriate for the characterization of the in-plane material properties. The use of thick specimens for mode I fracture toughness tests complicates the characterization and can lead to erroneous results. Contrary to what has been reported in the literature for the same material, fracture toughness in mode I is lower than for mode II, which agrees with the normal tendency of traditional composite materials.

Inertial force effects complicate the determination of the mode I interlaminar fracture toughness under high loading rates in composites. Although using a quasi-static analysis is a common approach, it is not always valid. A time-based threshold criterion is proposed to determine when dynamic effects might be neglected during the analysis of a high loading rate Double Cantilever Beam test. The criterion compares a transition time, time after which inertia effects can be neglected, versus the time for the initiation of fracture propagation. Three different methods are considered for the transition time. Good agreement is found when comparing the expressions with numerical simulations. It is also demonstrated that the transition time is affected by the velocity profile. The proposed criterion and approach to determine the transition time are useful tools to define when a quasi-static data-reduction scheme can be used.

Four different methods to experimentally determine the J\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal {J}$$\end{document}-curve of quasi-brittle materials are analysed and discussed in this work. The first two methods measure the integral of the cohesive law, J(ω)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal {J}(\omega )$$\end{document}, from an initial notch. However, the correct definition of the notch geometry is of critical importance for an accurate identification of the cohesive law. The other two methods measure J(ω)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal {J}(\omega )$$\end{document} when the crack is propagating with a fully-developed cohesive zone. In this case, the cohesive law is obtained by determining the crack opening displacement along the fracture process zone without requiring information about the geometry of the initial notch. The four methods are discussed highlighting the corresponding advantages, limitations and required experimental results. Then, the results of the four methods are compared and validated by considering the experimental results of the Compact Tension test of a quasi-isotropic carbon fibre composite laminate. Finally, some recommendations are given on which of the four methods is the most appropriate to characterise the material J(ω)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal {J}(\omega )$$\end{document} law based on the available measuring techniques.

Four different methods to experimentally determine the $$\mathcal {J}$$-curve of quasi-brittle materials are analysed and discussed in this work. The first two methods measure the integral of the cohesive law, $$\mathcal {J}(\omega )$$, from an initial notch. However, the correct definition of the notch geometry is of critical importance for an accurate identification of the cohesive law. The other two methods measure $$\mathcal {J}(\omega )$$ when the crack is propagating with a fully-developed cohesive zone. In this case, the cohesive law is obtained by determining the crack opening displacement along the fracture process zone without requiring information about the geometry of the initial notch. The four methods are discussed highlighting the corresponding advantages, limitations and required experimental results. Then, the results of the four methods are compared and validated by considering the experimental results of the Compact Tension test of a quasi-isotropic carbon fibre composite laminate. Finally, some recommendations are given on which of the four methods is the most appropriate to characterise the material $$\mathcal {J}(\omega )$$ law based on the available measuring techniques.

The National Academies of Sciences, Engineering, and Medicine commissioned an environmental scan describing the status of health care integration of oral health and primary care services.The authors conducted an environmental scan of US integration activities with publications from January 2000 through August 2017. They categorized services as preventive oral health services (POHS) provided by medical care providers, POHS provided by dental providers in nondental settings, preventive health services provided by dental providers, or care coordination using dedicated personnel and technology. The authors chose 4 programs as case studies and interviewed key personnel in each program. One case study illustrates each category of integrated services; additional examples describe category variation.The case study involving Into the Mouth of Babes illustrates medical professionals delivering POHS to children. The case study involving Grace Health presents dental hygienists embedded in the obstetrics-gynecology clinic to provide oral screening, prophylaxis, and education to pregnant women. At HealthPartners, medical care providers refer patients with diabetes to dentists and waive copays for periodontal care. The InterCommunity Health Network Coordinated Care Organization uses dedicated patient coordinators, technology, and coordinated payment and referral mechanisms to facilitate care.Integration of dental and medical care increased access to and coordination of patient care by means of offering health care services traditionally provided by the other profession.Integration models demonstrate the incorporation of POHS by primary care professionals, the embedding of dental professionals into primary care clinics, and the incorporation of care coordination to increase the delivery of oral health care. Similarly, dentists identify and refer patients with medical needs or preventive gaps to medical homes.

Reconocido como una de las figuras clave en la difusión de la inoculación contra la viruela en España, el médico de origen irlandés Timoteo O'Scanlan dejó publicadas 3 obras y numerosos artículos de prensa en los que plasmó su pericia e interés por una práctica que se inició de forma tardía en nuestro país. Aceptado como miembro de la Real Academia Médica de Madrid en noviembre de 1778, leyó su discurso de ingreso en abril de 1779. El texto, que constituye la primera aproximación de O'Scanlan a la inoculación, que venía practicando con éxito desde 1771, fue incluido con algunas modificaciones y sin citar la fecha de redacción en la introducción de su primera obra, Práctica moderna de la inoculación (1784). El manuscrito se encuentra en el Archivo del Conde de Campomanes (Fundación Universitaria Española, Madrid).Recognized as one of the key figures in the spread of inoculation against smallpox in Spain, the Irish doctor Timothy O'Scanlan published three books and numerous press articles that reflected his expertise and interest in a practice which began late in Spain. Accepted as a member of the Royal Academy of Medicine of Madrid in November 1778, he read his inaugural speech in April 1779. It was O'Scanlan's first approximation to inoculation, which he had been successfully practicing since 1771. The text was included with some modifications, without mentioning the date of the writing, in the introduction to his first book Modern Practice of Inoculation (1784). The manuscript is kept in the Archive of Conde de Campomanes (Fundación Universitaria Española, Madrid).

Évaluer l’informativité et la qualité des descriptions d’effets indésirables susceptibles d’être liés au baclofène, dans les forums de discussion français.Nous avons évalué la qualité des cas de pharmacovigilance potentiels associés au baclofène dans 22 forums de discussion. Nous avons ensuite comparé ces données aux cas de pharmacovigilance issus de la base nationale de pharmacovigilance (BNPV), en termes d’informativité concernant le patient, le traitement et l’effet indésirable ainsi que la gravité et le caractère inattendu des effets.Nous avons identifié 782 cas de pharmacovigilance potentiels parmi 2621 messages issus de forums français. L’informativité des messages des forums était significativement inférieure à celle des cas issus de la BNPV, pour l’ensemble des données concernant le patient (3 %/6 % vs 88 % pour l’âge/la classe d’âge et 46 % vs 99 % pour le sexe, respectivement), pour la durée de traitement (9 % vs 24 %) et pour l’évolution de l’effet indésirable (1 % vs 64 %, respectivement). Mais l’indication du traitement et sa posologie étaient plus fréquemment renseignées dans les forums que dans la BNPV (67 % vs 24 % et 27 % vs 9 %, respectivement). Les cas d’effets indésirables issus des forums sont très majoritairement non graves, contrairement à ceux issus de la BNPV (38 % vs 0,7 %). La proportion de cas rapportant des effets indésirables inattendus est significativement plus importante dans les forums que dans la BNPV (43,8 % vs 11,6 %).L’indication et la posologie étaient plus souvent renseignées dans les messages que dans la BNPV, ce qui fait des forums une ressource intéressante pour étudier les conditions d’utilisation du baclofène. Bien que les forums comportent plus d’effets inattendus, leur moindre informativité rend difficile l’évaluation de l’imputabilité. Nous estimons que les forums et la BNPV sont deux sources de données complémentaires pour la sécurité d’emploi du baclofène.To evaluate the informativity, quality of French discussion forums for evaluation of baclofen safety.We evaluated the quality of potential pharmacovigilance case reports associated to baclofen in 22 French discussion forums. We compared the informativity concerning the patient, treatment, seriousness and expectedness of adverse events described on these posts, with similar information coded in case reports from the French pharmacovigilance database (FPVD).A total of 782 potential case reports were identified among 2621 French language forums’ posts. Cases in the FPVD were significantly more informative than web forums’ posts for patient information (3%/6% vs. 88% for the age/class of age and 46% vs. 99% for the gender), treatment duration (9% vs. 24%) and outcome of the ADR (1% vs. 64%). But both indication and dose were more frequently retrieved in forums than in the FPVD (67% vs. 24% and 27% vs. 9%, respectively). Cases from web forums were significantly more frequently non-serious than the FPVD's ones (38% vs. 0.7%). Adverse events were significantly more often unexpected in forums than in the FPVD (43.8% vs. 11.6%).Indication and posology were more often documented in posts than in case reports which makes forums an interesting resource for monitoring use of baclofen. While posts contain more unexpected events, informativity is low which makes causality assessment difficult. Nevertheless, we consider forums as a secondary, but complementary source for pharmacovigilance about baclofen.