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Spurious damage modes in continuum damage mechanics models for fiber-reinforced polymer composite materials based on the effective stress tensor can be generated when large strains occur. A methodology to prevent this spurious phenomenon is developed in the present work. The longitudinal damage activation functions are based on the effective stress tensor, however, nominal stresses are used on the transverse damage activation functions. The proposed method can be straightforwardly implemented on previously-developed constitutive models which use the effective stress tensor, an explicit implementation of the proposed constitutive model is presented. The enhancement of the predicted failure mechanisms obtained from the present constitutive model, with respect to the models which use the effective stress tensor, is demonstrated. The proposed constitutive model presents a good agreement of the predicted failure pattern obtained from open-hole compressive experimental tests, as well as on the predicted failure strength., Postprint (published version)

Up to now, metal–organic frameworks (MOFs) with open nanostructures have shown outstanding capabilities in trapping smoke particles compared to the original MOFs. However, only a few MOF-based strategies have been reported to synthesize hierarchical porous cages thus far, which are mainly restricted to environmentally unfriendly wet-chemical liquid methods. Herein, as a proof-of-concept, a gas-steamed metal–organic framework approach was designed to fabricate a series of cheeselike open cages with hierarchical porosity. Briefly, zeolitic imidazolate framework-67 (ZIF-67) and phytic acid were employed as precursor and etchant, respectively. Abandoning the conventional wet-chemical method, the coordination bond of ZIF-67 was cleaved by acidic steam, forming an open framework with a high specific surface area and a hierarchical porous structure. The universality of this method was also confirmed by the selection of different etchants. Impressively, they also show outstanding fume-toxic adsorption capability and labyrinth effects based on abundant and complex porous channels. At only 5 wt % loading, Co3O4@open ZIF-67 cage-2 (Co3O4@OZC-2) imparted polyurea (PUA) composites with a 21.2% limiting oxygen index, and the peak of heat release rate, total heat release, and total smoke production were reduced by around 37.5, 25.5, and 40.4%, respectively, compared to neat PUA. This work will shed light on the advanced structural design of polymer composites with high fire safety, especially smoke suppression performance, so as to obtain more feasible applications, ​This work was supported by the National Natural Science Foundation of China (no. 22005029 and 22375023) and the BIT Research and Innovation Promoting Project (Grant No. 2023YCXY041). The authors extend their gratitude to Mr. Mengyun Cao from Shiyanjia Lab (www.shiyanjia.com) for providing invaluable assistance with the TME testing. The carbon-coated formvar film was provided by Zhongjingkeyi (Beijing) Film Technology Co., Ltd., Postprint (author's final draft)

The objective of this work was to design a mechanical prosthesis made of a polymer matrix composite material (epoxy resin) with laminated carbon fiber reinforcement (prepreg). The design was based on the patient’s current condition in terms of the degree of amputation (below-elbow amputation) and the simplified idealization of the possible tensional stress of the component under service conditions. The design was done using the SolidWorks CAD program. Personalized library of composite sheet material was created by manually inputting material parameters and their respective orientations. These composite material properties were computed by means of eLamX software based on the micromechanical model of Chamis. Finally, to ensure the proper prosthesis ́performance, a simulation of its mechanical behavior under service conditions was performed. This article was derived from a master’s thesis in Materials Engineering, conducted in a multidisciplinary approach within the Department of Graphic Engineering and Design at EEBE

The use of lime-based composites reinforced with fabrics made of natural fibers, is a promising solution for the strengthening of historical masonry structures owing to its moderate mechanical strength, similar color and chemical compatibility, avoiding damage on the historical structure and contributing to crack-width control. In this study, a new lime-based composite reinforced with flax nonwoven fabrics is mechanically characterized to study its reinforcement potential in terms of strength, and stress distribution. To this end, laminate plates with lime/metakaolin matrix and four to six layers of fabric reinforcement were produced and totally carbonated in a CO2 chamber. Both the mechanical (flexural and tensile) and durability (against wet-dry cycles) properties of the composite were subsequently assessed. Furthermore, Digital Image Correlation (DIC) was carried out on tensile testing to study the stress distribution. The 6-layer composites displayed the best performance (with flexural and tensile strengths of approximately 5.3 MPa and 2.5 MPa, respectively), followed by the 5-layer and the 4-layer composites. The DIC analysis revealed a higher stress distribution in the 6-layer composites, with an increased number of cracks, although having a lower severity. As for durability, a decrease of 30–45% is observed in flexural strength, and of 6–18% in tensile strength, depending on the number of reinforcing layers. SEM analysis refers to fiber/matrix debonding as the cause of this decrease. No damage has been observed on the fiber surface, which retains its reinforcing capacity. All of the composites displayed strain-hardening behavior in both the unaged and aged conditions. Study outcomes are intended to serve as the basis for the creation of a future, compatible, reliable, and sustainable system given its potential application in the historical restoration of masonry structures, The authors wish to express their gratitude to the Spanish government’s Ministerio de Ciencia e Innovación (MCIN) and Agencia Estatal de Investigación (AEI) for the financial support provided within the scope of the RECYBUILDMAT project (PID2019–108067RB-I00MICIN/ AEI/10.13039/501100011033), and the Generalitat de Catalunya’s Agència de gestió d’Ajuts Universitaris i de Recerca (AGAUR) for the financial support provided to the TECTEX Research Group (2021 SGR 01056). The author Heura Ventura is a Serra-Húnter fellow, Postprint (published version)

This work presents a novel formulation of a 3D smeared crack model for unidirectional fiber-reinforced polymer composites based on a stress invariant approach for transverse yielding and failure initiation, and on a continuum damage approach. This formulation is developed to facilitate the implementation in an implicit solver, increasing solution robustness and computational efficiency in quasi-static and long duration analyses. The performance of the model is evaluated using monotonic and non-monotonic damage evolution, verified with single element tests to demonstrate the consistency of the proposed formulation. Additional benchmark examples regarding off-axis tension and compression tests are simulated and compared with the experimental results, showing good agreement for the plastic response, failure load and failure strain., Postprint (published version)

Cellulosic fibers obtained from Barley straw were utilized to reinforce PHB. Four different processed fibers were employed as reinforcing material: sawdust (SW), defibered (DFBF), delignified (DBF), and bleached (BBF) fibers. The composite was processed from two different perspectives: a discontinuous (bach) and an intensification process (extrusion). Once processed and transformed into final shape specimens, the materials were characterized by mechanical testing (tensile mode), scanning electron microscopy, and theoretical simulations by finite elements analysis (FEA). In terms of mechanical properties, only the elastic moduli (Et) exhibited results ranging from 37% to 170%, depending on the reinforcement composition. Conversely, strengths at break, under both tensile and bending tests, tended to decrease, indicating poor affinity between the components. Due to the mechanical treatment applied on the fiber, DFBF emerged as the most promising filler, with mechanical properties closest to those of neat PHB. DFBF-based composites were subsequently produced through process intensification using a twin-screw extruder, and molded into flowerpots. Mechanical results showed almost identical properties between the discontinuous and intensification processes. The suitability of the material for agriculture flowerpots was demonstrated through finite analysis simulation (FEA), which revealed that the maximum von Mises stresses (5.38 × 105 N/m2) and deformations (0.048 mm) were well below the limits of the composite materials, This research was funded by Interreg program (POCTEFA 2014–2020), grant number Bioplast-EF 253/16. APC was funded by UdG. Dr. Oliver-Ortega acknowledges the funding of the research group TECTEX (2021 SGR 01056) from the Department de Recerca i Universitats de la Generalitat de Catalunya, Postprint (published version)

El mortero es uno de los materiales más resistentes que habitualmente se utiliza para revestimientos de paredes, rehabilitación y refuerzo de estructuras o en la construcción de infraestructuras que contribuyen al desarrollo de un país. El mortero es una mezcla homogénea que se compone principalmente de la mezcla de cemento, arena y agua, a la cual en ocasiones se le añaden aditivos para mejorar sus propiedades mecánicas y rendimiento. A veces, el mortero puro no cumple con las propiedades necesarias para resistir algunos de los esfuerzos a los que se ve sometido en algunas estructuras, por lo que este se suele reforzar con barras o mallas de acero. Debido a que el acero representa un elevado coste económico y medio ambiental, en la actualidad se está buscando nuevas alternativas a este material, como lo es por ejemplo el FRCM (Fiber-reinforced Cementitious Matrix), el cual tiene costes más reducidos y mucho más sostenible cuando se utilizan fibras vegetales, con el objetivo de disipar mayor energía frente a acciones de impacto puesto que este material tiene más capacidad de alargamiento y amortiguación. En este proyecto se analizará el comportamiento de placas compuestas de mortero reforzado con tejido de fibras vegetales (FRCM), así como con tejidos sintéticos como tejidos de vidrio y tejidos de acero frente a cargas de impacto. Para el desarrollo de dicho estudio, se elaborarán las probetas en los laboratorios de la UPC de Terrassa. Posteriormente las pruebas se llevarán a cabo mediante un test estandarizado denominado: Método de prueba estándar para medir la resistencia al daño de un compuesto de matriz polimérica reforzada con fibra ante un evento de impacto por peso caído (Designación: D7136/D7136M – 12). A continuación, se analizarán los datos recopilados para llegar a conclusiones basadas en los resultados obtenidos., Mortar is one of the most resistant materials commonly used for wall claddings, rehabilitation, and structural reinforcement, or in the construction of infrastructures that contribute to the development of a country. Mortar is a homogeneous mixture mainly composed of cement, sand, water, and sometimes additives are added to improve its mechanical properties and performance. Sometimes, pure mortar does not meet the necessary properties to withstand some of the efforts it is subjected to in certain structures, so it is often reinforced with some steel matrix (reinforced concrete). Due to the high economic and environmental cost of steel, currently, new alternatives to this material are being sought, such as FRCM, which has lower costs and is much more sustainable, with the goal of dissipating more energy in the face of impact actions since this material has greater elongation and damping capacity. In this project, the behavior of mortar plates reinforced with vegetable fiber fabric (FRCM) under impact loads with different materials will be analyzed. For the development of this study, the specimens will be prepared in the UPC laboratories in Terrassa. Subsequently, the tests will be carried out through a standardized test called: Standard Test Method for Measuring the Damage Resistance of a Fiber-Reinforced Polymer Matrix Composite to a Drop-Weight Impact Event (Designation: D7136/D7136M – 12). Then, the obtained data will be analyzed to be able to reach some conclusions with the results obtained.

El FRCM (Fabric Reinforced Cementitious Matrix), también conocido como TRM (Textile-Reinforced Matrix), se erige como un compuesto altamente prometedor para el refuerzo de estructuras antiguas o deterioradas por el transcurso del tiempo. Su composición lo hace perfectamente compatible con una amplia gama de materiales utilizados en construcción, desde elementos de mampostería antigua hasta diversos tipos de cemento y hormigón. Este compuesto se conforma mediante una matriz de mortero y un refuerzo en forma de malla, comúnmente compuesta por fibras textiles de origen sintético. Su aplicación se extiende al refuerzo de estructuras de hormigón armado y mampostería, emergiendo como una alternativa prometedora a los materiales previamente empleados en este contexto. La versatilidad del FRCM se manifiesta en su capacidad para adaptarse a diversas aplicaciones mediante ajustes en la malla o en la propia composición del mortero. En la actualidad, numerosos estudios buscan caracterizar las propiedades físicas y químicas de estos materiales, llevando a cabo una variedad de experimentos y ensayos con diferentes especímenes. Se exploran diversas combinaciones de morteros, mallas e incluso métodos de fabricación, delineando un campo de investigación en constante evolución. En este trabajo de fin de grado, se investiga la degradación de fibras vegetales, específicamente algodón, cáñamo y sisal, bajo la exposición a distintos entornos. Se abordan los procesos de degradación al sumergir las probetas de FRCM en agua, así como los mechones e hilos de manera individual en un medio alcalino. El documento detalla exhaustivamente el procedimiento utilizado para la fabricación de las distintas probetas, asegurando su correcta preparación para los ensayos. Después de llevar a cabo las pruebas, se concluye que, durante el período estudiado, en las probetas de FRCM la humedad o agua que penetra en el mortero no ha degradado las fibras de manera significativa. En los ensayos de hilos y mechon, The FRCM (Fabric Reinforced Cementitious Matrix), also known as TRM (Textile-Reinforced Matrix), emerges as a highly promising compound for reinforcing ancient or deteriorated structures over time. Its composition makes it perfectly compatible with a wide range of materials used in construction, from elements of ancient masonry to various types of cement and concrete. This compound is formed by a matrix of mortar and a reinforcement in the form of a mesh, commonly composed of synthetic textile fibers. Its application extends to the reinforcement of reinforced concrete structures and masonry, emerging as a promising alternative to materials previously used in this context. The versatility of FRCM is evident in its ability to adapt to various applications through adjustments to the mesh or the mortar composition itself. Currently, numerous studies seek to characterize the physical and chemical properties of these materials, conducting a variety of experiments and tests with different specimens. Various combinations of mortars, meshes, and even manufacturing methods are explored, outlining a constantly evolving field of research. In this undergraduate thesis, the degradation of plant fibers, specifically cotton, hemp, and sisal, is investigated under exposure to different environments. Degradation processes are addressed by immersing FRCM specimens in a neutral medium (water) and individual strands and threads in an alkaline medium. The document thoroughly details the procedure used for the manufacture of different specimens, ensuring their proper preparation for testing. After conducting the tests, it is concluded that, during the studied period, water has not penetrated the mortar structure, thus preventing fiber degradation. Remarkably, cotton has proven to be the most resistant material to the alkaline medium, exhibiting virtually insignificant degradation. On the other hand, a decrease in the maximum tensions obtained is observed for hemp and sisal, with the latte

A new methodology to measure the transverse Poisson’s ratios in fibre-reinforced composite materials was developed. Transverse tensile and transverse compressive standardised tests were instrumented using digital image correlation equipment to measure the lateral strain field of the specimens. A thermoplastic-based composite material was used to describe the proposed methodology. The elastic transverse Poisson’s ratio exhibits a different behaviour in tension than in compression, its value being greater in compression than in tension. Assuming no plastic strain in the longitudinal direction, the plastic transverse Poisson’s ratio in compression suggests no volumetric plastic strains for small axial plastic strains, however, plastic dilatancy was observed when the amount of compressive plastic axial strain increases., Postprint (published version)

After conducting a comprehensive historical review of presently established methods for computational modeling of multilayered bending plates, the present work introduces a novel 2D multiscale strategy, termed the 2D+ approach. The proposed approach is based on the computational homogenization formalism and is envisaged to serve as an appealing alternative to current methodologies for modeling multilayered plates in bending-dominated situations. Such structural elements involve modern and relevant materials, such as laminated composites characterized by the heterogeneous distribution of low-aspect-ratio layers showing substantial non-linear mechanical behavior across their thickness. Within this proposed approach, the 2D plate mid-plane constitutes the macroscopic scale, while a 1D filament-like Representative Volume Element (RVE), orthogonal to the plate mid-plane and spanning the plate thickness, represents the mesoscopic scale. Such RVE, in turn, is capturing the non-linear mechanical behavior throughout the plate thickness at each integration point of the 2D plate-midplane finite element mesh. The chosen kinematics and discretization at the considered scales are particularly selected to (1) effectively capture relevant aspects of non-linear mechanical behavior in multilayered plates under bending-dominated scenarios, (2) achieve affordable computational times (computational efficiency), and (3) provide accurate stress distributions compared to the corresponding high-fidelity 3D simulations (computational accuracy). The proposed strategy aligns with the standard, first-order, hierarchical multiscale setting, involving the linearization of the macro-scale displacement field along the thickness. It employs an additional fluctuating displacement field in the RVE to capture higher-order behavior, which is computed through a local 1D finite element solution of a Boundary Value Problem (BVP) at the RVE. A notable feature of the presented 2D+ approach is the application, The authors gratefully acknowledge the financial support received from the Spanish Ministry of Science and Innovation through the ’Proyectos de Transición Ecológica y Digital 2021’ programme under grant TED2021-129413B-C21, the ’Generación de Conocimiento 2022’ programme under grant PID2022-140249OB-I00 and the Catalan Agency for Management of University and Research Grants through the ’Convocatòria ajuts d’Indústria del Coneixement: Producte, 2021’ under grant PROD 00016. Dr. Oriol Lloberas-Valls gratefully acknowledges the financial support received from he Spanish Ministry of Science and Innovation, through the ’Consolidación Investigadora 2022’ programme under grant CNS2022-135900. CIMNE is a recipient of a “Severo Ochoa Programme for Centers of Excellence in R &D” grant (CEX2018-000797-S) by the Spanish Ministry of Economy and Competitiveness., Peer Reviewed, Postprint (published version)

Aquest projecte descriu el procés d'elaboració d'una carta de material per a anàlisi d'elements finits amb un mètode de càlcul explícit. Amb aquesta, es pretén dissenyar i construir un coet fet de materials compostos amb l'objectiu de competir a l'EuRoC., Este proyecto describe el proceso de elaboración de una carta de material para el análisis de elementos finitos con un método de cálculo explícito. Con ella, se pretende diseñar y construir un cohete hecho de materiales compuestos con el objetivo de competir en el EuroC., This project describes the process of preparing a material card for finite element analysis with an explicit calculation method. With this, it is intended to design and build a rocket made of composite materials with the aim of competing in the EuRoC.

Fiber reinforced polymer composites employed in industries such as aerospace and automotive, are susceptible to deteriorate over time as a result of impact and moisture absorption. With the widespread use of composite materials, the demand for technologies capable of repairing damaged components rather than replace them has increased in past decade. Additionally, the use of bio-based constituents in composites materials shows an upward trend in the industry. This work will focus on repairing natural fiber reinforced composites, specifically Flax-based composites. For this purpose, two formulations of resin are utilized, a bio-based epoxy resin and a vitrimer resin. Each resin system undergoes a distinct repair technique: injection repair for epoxy-based composites and forming for vitrimer-based ones. The specimens were produced using vacuum assisted resin infusion. The specimens were cut from these plates. A drop weight impact machine was used to damage the specimens in controlled, low-velocity impact test. The repair process for damaged epoxy-based specimens involves resin injection aided by vacuum. The damaged vitrimer-based specimens were formed over a four-hour period within a heating press operating at 160 °C. The efficiency of the repair methods was assessed using active thermography and compression after impact test. Both evaluation techniques demonstrated that the injection repair technique produced favorable results, demonstrating the effectiveness of the repair method for the chosen system. Although the thermographic outcome from the forming technique were positive, the compression properties highlights is ineffectiveness for the chosen natural fiber and vitrimeric system., Outgoing

The use of more environmentally friendly materials is gaining increased acceptance in strengthening historic masonry structures. Therefore, using vegetable nonwoven fabric as reinforcement in the lime composite may be a promising solution. This study presents a comparison extensive experimental program carried out on two flax nonwoven fabric reinforced lime composites ( CL-90 and putty CL-90) modified with two kinds of various metakaolin (MK). Laminate plates comprising six layers of fabric impregnated with a lime matrix were created and cured in a CO2 chamber for up to 7 days and both the mechanical (flexural and direct tension) Further and scanning electron microscopy (SEM) was used to complement the analysis of mechanical characterization. The results confirmed that the 6 layers composites with Putty LC-90 lime had a better mechanical performance. The results and outcomes of this study may serve as the basis for future research on these composites and their potential use in structural applications in the building construction and restoration of historical masonry structures, Postprint (published version)

Según la Organización de las Naciones Unidas para la Alimentación y la Agricultura (FAO), cerca al 30% de la producción global de alimentos, se desperdicia durante su cosecha, procesamiento y consumo final, un equivalente a 1.300 millones de toneladas al año, lo que supone cantidades ingentes de recursos destinados a la producción de alimentos que se usan inútilmente. En la actualidad, la revalorización de subproductos agrícolas o agroindustriales siguen teniendo un carácter tradicional, lo que significa una pérdida de valor con un alto potencial de aprovechamiento. En ese sentido y como alternativa a este tipo de aplicaciones con bajo o nulo valor, está claro el planteamiento de nuevas propuestas de valorización, como por ejemplo la obtención de nuevos materiales, donde la idea fundamental es la de aprovechar estos subproductos. El presente Trabajo de Fin de Máster tiene como objetivo realizar un estudio que contenga una parte importante del sector agroalimentario o agrícola en Catalunya, desde el punto de vista de generación de subproductos y las posibilidades de revalorización que existe de estos, sobre todo enfocados en el aprovechamiento de los subproductos de naturaleza fibrosa y su potencial en cuanto aplicaciones en nuevos materiales, de esta manera contribuir a la economía circular utilizando recursos biodegradables. En primer lugar, se realizará una descripción de la industria agroalimentaria global y catalana, seguidamente se analizará las principales fuentes agrícolas con mayor peso en Catalunya y se hablará de la situación actual en un contexto global de estos cultivos, a continuación, se hará un breve resumen de carácter morfológico de los cultivos con mayor volumen de producción. Se analizará los subproductos generados, donde se apreciará el tipo y cantidad, recogiendo datos estadísticos, así como referencias bibliográficas sobre coeficientes de generación de subproductos del procesamiento de alimentos. Por último, ya en una parte más experimental del

Els composites termoplàstics reforçats amb fibra de carboni han esdevingut cada vegada més populars. El rendiment mecànic d'aquests composites depèn de diversos factors, incloent la qualitat de la impregnació de fibra en la matriu. L’aprest, conegut com a sizing, aplicat a la fibra de carboni durant el seu procés de fabricació és un factor important que influeix en la impregnació de la matriu i per lo tant en el rendiment mecànic del composite resultant. El sizing afecta les propietats interficials de la interfície fibra-matriu. Per tant, comprendre la influència d’aquest sizing en la impregnació i el rendiment mecànic dels composites de termoplàstic és crucial per optimitzar el disseny i la fabricació d'aquests materials. En aquest projecte, l'objectiu és investigar la influència del sizing de la fibra de carboni en el procés de laminació, impregnació i propietats mecàniques dels composites de termoplàstic reforçats amb fibra de carboni. S’han avaluat diferents mostres tractades entre temperatures de 400ºC fins a 800ºC i una mostra no tractada, realitzant un FT-IR a cada una per comprovar la composició química de cada mostra. Posteriorment, s’ha laminat cada mostra amb una pel·lícula de poliamida biobasada per comprovar si macroscòpicament es pot apreciar alguna diferència. Seguidament s’ha termoconformat cada mostra per realitzar proves de tracció i flexió per comparar els diferents resultats mecànics i, finalment, s’han observat amb microscopi les diferents zones de trencament produïdes per la prova de tracció. S’ha conclòs que un tractament tèrmic a 400ºC al teixit de carboni es millora la interfase entre la fibra i la matriu, també es millora la impregnació i el rendiment mecànic, tant en la resistència a tracció com a flexió. S’ha observat que si el tractament tèrmic es realitza a una temperatura més alta, tot i que el rendiment mecànic pot resultar més alt que amb la mostra no tractada, la fibra de carboni perd propietats i estructura

Sandwich panels composed of fabric-reinforced cementitious matrix (FRCM) and extruded polystyrene foam (EPS) represent a light and insulating solution compared with other types of enclosure walls, such as steel-reinforced concrete (RC) panels. To improve the sustainability and lightness of FRCM sandwich panels used for building enclosures, this study proposes the use of hemp fabrics in contrast to glass fabrics. Modal analysis and bending and compression tests were conducted on full-scale panels with hemp- and glass-FRCMs. The results obtained from these tests indicate that the use of hemp fabrics with greater equivalent thickness and deformation capacity than glass fabrics make the production of ductile and strength (35 % more than glass-FRCM) sandwich panels possible. Nevertheless, glass-FRCMs allow the production of more stiffened panels. In addition, this study presents a simplified analytical model of sandwich FRCM panels based on the definition of cracked section strength, which is useful in the case of full composite action in the sandwich solution., This study has been partially carried out within the project ‘‘Desarrollo de paneles industriales prefabricados tipo sándwich con materiales compuestos de matriz cementicia (FRCM) y con digitalizacion ´ BIM incorporada. PANELPLUS’’, funded by the Spanish Ministry of Science, Innovation and University through the Torres Quevedo program. The materials support of Sika AG and Mapei Spain S.A. is acknowledged. Authors want to thanks the research project SEVERUS (RTI2018- 099589-B-I00) of the Spanish Research Agency. Second author is a Serra Húnter Fellow., Peer Reviewed, Postprint (author's final draft)

La indústria tèxtil és una de les indústries amb major controvèrsia ambiental, entre altres, els residus tèxtils. Aproximadament es produeix un milió de tones de residu tèxtil en l'àmbit estatal, de les quals només el 12% es recicla. El 88% restant acaba en un abocador controlat sense extreure'n profit o incinerat. No obstant això, el 2025, entrarà en vigor una nova normativa europea que exigirà la implementació d'un sistema de recollida municipal d'aquesta fracció de residus. Tot i la millora de la recol·lecció, existeix una necessitat de trobar alternatives per al reciclatge d'aquests residus, i és per això que neix la proposta d'aquest projecte. Un projecte on es vol donar una sortida a les peces de roba usada que ja no tenen ús, construint una nova funció en el món de la construcció. En aquest estudi s'ha volgut avaluar la degradació de diferents fibres post-consum quan són emprades com a reforç en materials compòsits de base ciment. Aquesta degradació és provocada per l'alcalinitat del ciment i podria donar lloc a una pèrdua de propietats del material compost. L'estudi es realitzarà mitjançant residus tèxtils que no es puguin reutilitzar convertits en estructures no teixides, mitjançant un triturat mecànic i un punxonat que permetran actuar com a reforç d'un material cementici. Per avaluar aquest estudi, s'utilitzaran dos mètodes d'assaig. Un assaig amb ciment Portland, amb 25 cicles d'assecat i humit que simulen la degradació accelerada del ciment. I un altre assaig on se simula el ciment, i s'avaluen el comportament dels components no suplementaris del ciment

En aquest projecte s’ha estudiat el comportament a tracció dels FRCMs pretesats, més concretament els reforçats amb malles vegetals. A partir d’un procés de fabricació i assaig dels espècimens, s’ha pogut estudiar el comportament d’aquests a tracció. Aquests assajos doncs, ens han permès assolir l’objectiu d’aquest projecte, entendre millor la influència del pretesat en tots els seus aspectes, passant per la fabricació, la realització d’assajos, l’estudi dels resultats obtinguts i tota la documentació i recopilació d’informació aportada. L’aplicació i del disseny del pretesat ha sigut un repte i un element clau alhora de poder obtenir els resultats Per tal de poder fabricar els FRCMs de forma eficient, s’han hagut d’adaptar els processos de fabricació. En aquest document s’explica tant l’us com la descripció d’estris i eines diferents als comuns per a la fabricació de FRCMs, mètodes d’aplicació i el monitoratge pretesa. Paral·lelament s’ha documentat tot aquest procés, explicant més en detall tota la metodologia emprada. La realització dels assajos i l’estudi de resultats, ha mostrat el comportament dels FRCMs pretesats, amb la comparació d’aquests amb espècimens de control s’ha pogut observar com la pretesa no sempre suposa millores de propietats, i en alguns casos no es veuen millores i inclús les redueix. Per acabar, també s’ha avaluat l’impacte ambiental i social que ha suposat la realització d’aquest, amb l’objectiu de poder quantificar de forma aproximada les emissions de CO2 que s’han generat. D’aquesta es pot tenir en compte alhora de realitzar projectes similars.

La present tesi aspira a estudiar les juntes d'estructures de formigó armat amb materials compostos per a parets gruixudes com en edificis nuclears des del punt de vista del model de contacte. L'anàlisi i l'estudi aniran encapçalats pel mètode dels elements finits per a la simulació numèrica. Es seguirà una literatura específica existent com a referència per a la base principal de la tesi, que ajudarà a validar el model d'algorisme de contacte per tal de simular amb mètodes numèrics. A més, l'objectiu d'analitzar els algorismes de contacte disponibles per demostrar les solucions en un model de contacte dins d'una metodologia específica. L'eina per desenvolupar i obtenir aquests resultats serà la interfície del programa d'Abaqus. Mentre que, s'utilitzarà com a eina per determinar les diferents geometries, condicions límit i càrregues en aquesta tesi mitjançant un model numèric d'unions per a parets compostes gruixudes. A més, el projecte ofereix un estudi i la seva aplicació del model constitutiu per a una futura línia de recerca en l'àmbit dels murs nuclears. Per a la seva primera aproximació i validació s'han estudiat diversos tipus de contactes. La tesi finalitza amb la validació d'un contacte final de parets gruixudes compostes per a instal·lacions nuclears segons els objectius principals, contrastats dins dels treballs existents per garantir la solució., La presente tesis aspira a estudiar las uniones de estructuras de hormigón armado con materiales compuestos para muros gruesos como en edificios nucleares desde el punto de vista del modelo de contacto. El análisis y estudio estará encabezado por el método de elementos finitos para simulación numérica. Se seguirá una literatura específica existente como referencia para la base principal de la tesis, que ayudará a validar el modelo del algoritmo de contacto para simularlo con métodos numéricos. Además, el objetivo de analizar los algoritmos de contacto disponibles para probar las soluciones en un modelo de contacto dentro de una metodología específica. La herramienta para desarrollar y obtener estos resultados será la interfaz del programa Abaqus. Mientras que, en esta tesis se utilizará como herramienta para determinar las diferentes geometrías, condiciones de contorno y cargas a través de un modelo numérico de juntas para muros compuestos de espesor. Además, el proyecto aporta un estudio y su aplicación del modelo constitutivo para una futura línea de investigación en el campo de los muros nucleares. Para su primera aproximación y validación se han estudiado varios tipos de contactos. La tesis finaliza con la validación de un contacto final de muros gruesos compuestos para instalaciones nucleares según los objetivos principales, contrastados con los trabajos existentes para asegurar la solución., The present thesis aspirates to study the joints for reinforced concrete structures with composite materials for thick walls as in nuclear buildings from a contact model point of view. The analysis and study will be headed by the finite element method for numerical simulation. It will be followed a specific existing literature as a reference for the main basis of the thesis, which will help to validate the contact algorithm model so as to simulate with numerical methods. Furthermore, the goal of analyzing the available contact algorithms to prove the solutions in a contact model within a specific methodology. The tool for developing and obtaining these results will be the program interface of Abaqus. Whereas, it will be used as a tool to determine the different geometries, boundary conditions and loads in this thesis through a numerical model of joints for thick composite walls. In addition, the project gives a study and its application of the constitutive model for a future line of research in the nuclear walls field. For its first approach and validation several types of contacts have been studied. The thesis ends with the validation of a final contact of composite thick walls for nuclear facilities according to the main objectives, contrasted within existing papers to ensure the solution.

Uno de los mayores retos respecto a las consideraciones ambientales es la gestión eficaz de los residuos provenientes de diferentes industrias a nivel mundial, especialmente de la industria textil y la industria hortofrutícola. Con relación a los desechos, la edición de 2018 de What a Waste 2.0: A global Snapshot of Solid Waste Management to 2050, estimó que la producción mundial de residuos sólidos municipales será de 2,01 billones de toneladas por año y se prevé que aumente a 3,4 billones de toneladas por año para 2050 [1]. El sector textil y de la moda han sido definidas como industrias que conllevan un alto gasto de recursos a lo largo de toda la cadena de valor. La fabricación de tejidos y en general de productos textiles terminados, abarca diferentes procedimientos que van desde la obtención de las fibras hasta el material o producto finalizado. Estos procesos requieren en su mayoría el uso de productos químicos, un elevado volumen de agua y energía, además de la generación de aguas residuales y de desechos textiles que no siempre tienen un plan de reciclaje o reutilización, por lo que suelen terminar desechados en vertederos o incinerados, causando así emisión de gases efecto invernadero (GEI) y en general un alto índice de contaminación al medio ambiente. Solo en la Unión Europea (UE) los consumidores desechan alrededor de 5,8 millones de toneladas de textiles al año [2], cifra que no incluye los desechos provenientes de la industria textil y de la moda a lo largo de los diferentes procesos hasta llegar al producto final. Por otro lado, la industria hortofrutícola y más específicamente la relacionada con la productora de manzana, se dedica principalmente a la cosecha y venta del fruto fresco ya sea como fuente de alimento o para diferentes industrias que lo procesan en productos como zumos, sidras, vinagres, entre otros. Estas industrias procesadoras del fruto de manzana generan un tipo de desecho orgánico conocido como orujo de manzana, el cual está compues

Actualment estem vivint en una època que s’està produint un moviment on molts sectors aposten per la sostenibilitat, com és el cas de l’automobilístic. Aquest treball neix amb l’objectiu de dissenyar un carenat de motocicleta elèctrica per a la competició MotoStudent amb una alternativa de materials compostos més sostenible. Per a fer-ho, en primer lloc es realitza una fase d’investigació tant des de la vessant tèxtil com la de disseny, seguit de la fase de conceptualització, el disseny CAD i gràfic d’aquest, les simulacions del disseny i finalment l’estudi de la seva possible producció (anàlisi i valoració de les implicacions ambientals i socials, definició i cerca de proveïdors i pressupost). El resultat d’aquest projecte és el desenvolupament conceptual i disseny d’una proposta alternativa de materials compostos més sostenible pel carenat del prototip de l’equip de MotoSpirit ESEIAAT

The growing knowledge and awareness of the environmental condition have driven to governments to implement restrictions on energy use, levels of efficiency and resources use, aiming for higher sustainability targets. Transportation an energy sectors have found on CFRP (Carbon Fiber Reinforced Polymers) technology a solution to achieve the highest levels of mechanical performance under low weights and is therefore a key enabling technology that makes possible the electric and hydrogen vehicles, the wind energy production and reduced levels of air transport emissions among others. This Master Thesis comprehends the study of the CFRP technological from a technical and market perspective pursuing the holistic comprehension of the system. This analysis will employ bibliographic references, quantitative and qualitative analysis and graphical visualizations to decompose complexity and to compile key data for the reader. For market forecasting time series forecasting techniques will be employed. At technical level the study covers the definition of the CFRP systems and subsystems/components, their characterization, production, manufacturing, the state of the art on the design methodology, recyclability and life-cycle assessment. This study will also detail current applications of the CFRP technology on multiple products. The market study involves the analysis of the European political context and regulations affecting CFRP adoption, the stakeholders of the system, the cost analysis of the CFRP, market quantification and the future market forecasting. The study produced has compiled relevant information from multiple sources in a summarized, relational and organized way, it has also produced useful datasets of CFRP technology and market; qualitative and quantitative analysis together with data visualization techniques have revealed multiple insights. The lifecycle assessment has quantified the environmental effects of CFRP production. A forecast of CFRP sells, prices and mar

Recentment, els materials compostos de fibra vegetals han anat guanyant força com a objecte d'estudi a causa de les seves propietats avantatjoses com ara el baix cost, la biodegradabilitat o el caràcter sostenible. En aquest treball es realitza un estudi teòric dels materials compostos de fibres vegetals per tal de poder plantejar una solució sostenible al desenvolupament de les estructures de baix cost que existeixen avui dia al Brasil. Per això, s'han elaborat diverses investigacions al voltant de les condicions actuals del Brasil, una definició dels materials compostos de fibres vegetals, així com una sèrie de tipologies d'aquestes de les quals se n'han obtingut les propietats mecàniques. En aquest punt es repararà a la prometedora opció de la fibra vegetal com a reforç d'una matriu cementícia en millorar les seves propietats mecàniques com ara la resistència a tracció, la tenacitat o la durabilitat del compost. La segona part del projecte té com a finalitat triar la fibra més convenient per al seu ús al Brasil. Segons uns criteris de producció, viabilitat i fiabilitat, s'ha triat la fibra vegetal de sisal com la indicada per reforçar matrius cementícies, per la qual cosa s'ha contextualitzat d'una forma més extensa aquesta fibra vegetal realitzant un recorregut històric tant al Brasil com al món, així com també una anàlisi de les seues propietats i característiques més al detall. Per concloure, s'ha vist de quina manera s'aplica la solució proposada en exemples pràctics i, alhora, el potencial que té per reforçar construccions de cara al futur., Recientemente, los materiales compuestos de fibra vegetales han ido ganando fuerza como objeto de estudio debido a sus ventajosas propiedades tales como su bajo coste, su biodegradabilidad o su carácter sostenible. En el presente trabajo se realiza un estudio teórico de los materiales compuestos de fibras vegetales con el fin de poder plantear una solución sostenible al desarrollo de las estructuras de bajo coste que existen hoy en día en Brasil. Para ello, se han elaborado diversas investigaciones en torno a las actuales condiciones de Brasil, una definición de los materiales compuestos de fibras vegetales, así como una serie de tipologías de éstas de las que se han obtenido sus propiedades mecánicas. En este punto se reparará en la prometedora opción de la fibra vegetal como refuerzo de una matriz cementícia al mejorar sus propiedades mecánicas tales como la resistencia a tracción, la tenacidad o la durabilidad del compuesto. La segunda parte del proyecto tiene como fin elegir la fibra más conveniente para su uso en Brasil. Según unos criterios de producción, viabilidad y fiabilidad, se ha elegido la fibra vegetal de sisal como la indicada para reforzar matrices cementícias, por lo que se ha contextualizado de una forma más extensa dicha fibra vegetal realizando un recorrido histórico tanto en Brasil como en el mundo, así como también un análisis de sus propiedades y características más al detalle. Para concluir, se ha visto de qué manera se aplica la solución propuesta en ejemplos prácticos y, a su vez, el potencial que tiene como para reforzar construcciones de cara al futuro., Recently, plant fiber composite materials have been gaining strength as an object of study due to their different properties such as their low cost, their biodegradability or their sustainable character. In the present work, a theoretical study of plant fiber composite materials is carried out in order to propose a sustainable solution to the development of low-cost structures that exist today in Brazil. For this purpose, several researches have been elaborated around the current conditions in Brazil, a definition of plant fiber composite materials, as well as a series of typologies of these from which their mechanical properties have been obtained. At this point, the promising option of vegetable fiber as reinforcement of cementitious matrix by improving its mechanical properties such as tensile strength, toughness or durability of the composite will be discussed. The second part of the project aims at choosing the most suitable fiber for use in Brazil. According to production, feasibility and reliability criteria, the sisal vegetable fiber was chosen as the most suitable for reinforcing cement matrices, so that a more extensive contextualization of this vegetable fiber was carried out by making a historical review both in Brazil and in the world, as well as a more detailed analysis of its properties and characteristics. In conclusion, it has been shown how the proposed solution is applied in practical examples and, in turn, the potential it has to reinforce constructions for the future.

The authors acknowledge the financial support of this work given by the Ministerio de Ciencia e Innovación (Spain) through the project “UpECOBLENDS” with reference PID2019-106518RB-I00. The authors also thank the Generalitat de Catalunya for the Grant 2021SGR01042. Lucia G. De la Cruz acknowledges the Grant (No. 729201) received from the Consejo Nacional de Ciencia y Tecnología CONACYT (México). The Aerogels Cost Action CA18125 is also acknowledged, Postprint (published version)

In this study, the mechanical behavior under monotonic loads of tungsten carbide-cobalt (WC-Co) composites is investigated extensively by analyzing (1) nanoindentation tests on WC particles and Co matrix, (2) nanowires made of WC-Co composites tested in tension and (3) micropillars made of WC-Co composites tested in compression. To this end, a novel computational framework consisting of two different microplane constitutive models developed for WC and Co phases are proposed. For the Co matrix, the microplane J2-plasticity, called the model MPJ2, and for the WC particles a modified version of the microplane model M7, called the model M7WC, are employed. Furthermore, finite element meshes in 3D obtained from experimental tomography reconstructions of WC-Co composites are employed to rule out any spurious geometric features that is likely to be encountered in artificially generated meshes. After calibrating the aforementioned models, it is shown that the finite element predictions not only confirm the extensive experimental observations but also shed further light into the mechanical behavior of these composites., Peer Reviewed, Postprint (published version)

Aquest projecte sorgeix amb l'objectiu d'apropar els materials compostos a un públic general. Aquesta família de materials és molt interessant a causa de les seves altes propietats específiques, elèctriques i tèrmiques. La gran innovació que presenten, però, té l'inconvenient d'encara un elevat cost econòmic. Partint d'aquest impediment, i amb la finalitat anterior, es proposa baixar el cost atribuït al disseny i fabricació dels motlles. Aquest cost és gran ja que tradicionalment s'han fabricat mitjançant mecanitzat. Aquesta tecnologia, tot i haver-se demostrat molt efectiva per a aquesta tasca, requereix un procés de disseny i maquinària cars. Així doncs, per a baixar el cost, es planteja una altra tecnologia de fabricació, la fabricació additiva mitjançant impressió 3D. El treball consisteix a documentar tot el procés d'implementació de la impressió 3D en la fabricació dels motlles per a tal que el lector el pugui repetir el procés i aconseguir motlles en un procés més econòmic i ràpid. Els resultats obtinguts permeten afirmar que si és possible fabricar materials compostos amb motlles d'impressió 3D., Este proyecto nace con el objetivo de acercar los materiales compuestos a un público general. Esta familia de materiales, es muy interesante gracias a sus altas propiedades específicas, eléctricas y térmicas. La gran innovación que presentan, tiene el inconveniente de aún un elevado coste económico. Partiendo de este impedimento, en conjunto con el objetivo anterior, se propone bajar el coste asociado al diseño y fabricación de los moldes. Este coste es grande ya que tradicionalmente, se han fabricado mediante tecnologías de mecanizado. Estas, aunque muy efectivas para esta tarea, requieren de un proceso de diseño y maquinaria caros. Así pues, para bajar el coste, se plantea usar otra tecnología de fabricación, la fabricación aditiva mediante impresión 3D. El trabajo consiste a documentar todo el proceso de implementación de la impresión 3D en la fabricación de los moldes para que el lector pueda repetir el proceso y conseguir moldes más económicos y rápidamente. Los resultados obtenidos permiten afirmar que si es posible fabricar materiales compuestos con moldes de impresión 3D., This project was born with the aim of bringing composite materials to a general public. This family of materials is very interesting thanks to its high specific properties, electrical and thermal. The great innovation they present, has the disadvantage of still a high economic cost. Based on this impediment, in conjunction with the previous objective, it is proposed to lower the cost associated with the design and manufacture of molds. This cost is great. Traditionally, they have been manufactured using machining technologies. These, although very effective for this task, require an expensive design process and machinery. So, to lower the cost, it is proposed to use another manufacturing technology, additive manufacturing using 3D printing. The project consists of documenting the entire process of implementing 3D printing in the manufacture of molds so that the reader can repeat the process and get molds more economically and quickly. The results obtained allow us to affirm that it is possible to manufacture composite materials with 3D printing molds.

Fibre and textile-reinforced mortars are increasingly being used for a variety of building applications, including the strengthening of masonry structures. Lime mortars reinforced with sustainable fibres (such as vegetable or cellulosic fibres) may provide an interesting solution. In this paper, a mixture of commercial lime with 20% metakaolin addition was used to produce composites reinforced with non-woven flax fabrics that were cured at different moisture contents (from 0 to 100%) for 7 or 14 days in a CO2 incubator. The composites were char- acterised to determine their flexural behaviour, carbonation level and microstructure. According to the results, no differences exist in the flexural strength of the composites made in the moisture range of 33%–66%. At 7 days of curing, they attained Modulus of Rupture (MOR) values that exceeded 5.5. MPa. Moreover, it was observed that under high moisture conditions, the permeability of the fibres allows for CO2 access, despite the saturation of the pores of the matrix – allowing a reaction in the vicinity of the fibres –, while under dry conditions, the fibre’s moisture retention does not permit the carbonation of the matrix in their vicinity, even though complete carbonation takes place after 14 days, Postprint (published version)

This report details ways to improve the mechanical properties of cement mixtures reinforced by nonwoven recycled fabrics. With improved mechanical properties nonwoven recycled fabrics will become viable in more applications. A study of penetration has been conducted by testing 5 different cement mixes and their penetrability with a vacuum pump on non-woven fabrics. A short study has been concluded about the best way to wet and penetrate the fabrics. To evaluate the levels of penetration the samples are put under a SEM microscope. Another way of improvement discussed in this study is a study on the effect of long fibers with short fibers in the mechanical performance of non-woven fabrics. In order to study their effects flax fibers (long fibers) are mixed with recycled fibers (short fibers) with different percentages from (100%,40%,30%,20%,10%,0%). The webs of the fabrics were prepared with an air lay machine and consolidated with needle punching to form the nonwoven fabrics. The mechanical performance of the nonwoven fabrics is tested using a tensile strength machine. It was found that the difference in penetrability between the mixes with superplasticizer and a dry powder (Fly ash, Limestone powder, Ground granulated blast furnace slag) were negligible when looked at the expected deviation in results. It was also found that improving the mechanical properties of a short fiber non-woven fabric is possible by adding long fibers to the fabric., Este informe detalla las formas de mejorar las propiedades mecánicas de las mezclas de cemento reforzadas con telas recicladas no tejidas. Con la mejora de las propiedades mecánicas, las telas no tejidas recicladas serán viables en más aplicaciones. Se ha realizado un estudio de penetración probando 5 mezclas de cemento diferentes y su penetrabilidad con una bomba de vacío en telas no tejidas. Se ha concluido un breve estudio sobre la mejor forma de humedecer y penetrar los tejidos. Para evaluar los niveles de penetración, las muestras se colocan bajo un microscopio SEM. Otra forma de mejora discutida en este estudio es un estudio sobre el efecto de las fibras largas con fibras cortas en el rendimiento mecánico de las telas no tejidas. Para estudiar sus efectos, se mezclan fibras de lino (fibras largas) con fibras recicladas (fibras cortas) en diferentes porcentajes (100%, 40%, 30%, 20%, 10%, 0%). Las bandas de los tejidos se prepararon con una máquina de tendido por aire y se consolidaron con punzonado de aguja para formar los tejidos no tejidos. El rendimiento mecánico de las telas no tejidas se probó utilizando una máquina de resistencia a la tracción. Se comprobó que la diferencia de penetrabilidad entre las mezclas con superplastificante y un polvo seco (cenizas volantes, polvo de piedra caliza, escoria de alto horno granulada molida) era insignificante si se observaba la desviación esperada en los resultados. También se descubrió que es posible mejorar las propiedades mecánicas de una tela no tejida de fibra corta añadiendo fibras largas a la tela., Incoming

Nowadays, the search for new materials with a sustainable character to reduce the production of residues is under continuous research. In this sense, fully biodegradable composites based on polyhydroxybutyrate and different pretreated fibres coming from barley straw have been fabricated, and their resistance to environmental controlled conditions have been characterized. The materials were already compounded in a kinetic mixer and injection-moulded as specimens for tensile assay to be aged in a Xenotest chamber so as to simulate environmental conditioning. The samples, after accelerated aging, were characterized thus: mechanical characterization (tensile assay), water uptake (immersion and contact angle), and surface observation (optical and SEM microscopy). The incorporation of the fibres helps the composite to keep its structure for a longer time. On the other hand, the presence of the fibres increases the water uptake capacity to allow water permeation in the composite, which allows final degradation, characterised by a significant drop in properties after one month of exposure to simulated environmental conditions., Peer Reviewed, Postprint (published version)

Fabric reinforced cementitious matrix (FRCM) are a type of sustainable materials for structures strengthening and envisaging to develop new construction solutions. However, the wide range of possible combinations of fabric and cementitious matrixes makes it necessary to study the particular contribution of mortar and fabric in the composite action of the FRCM. In this line, this study presents the experimental, analytical and numerical evaluation of the tensile behaviour of FRCM composites. 85 FRCM specimens of different thicknesses were manufactured, with one or two embedded fabrics of different type of fibres and geometry. Fabrics made of coated vegetal fibres were also considered to be compared with commercial fabrics of coated synthetic fibres. The results show a significant increase of the ultimate tensile strength with the increase of the FRCM thickness due to a residual contribution of the mortar after the cracking stage. The analytical model was effective for the cases that showed a cracking stabilization stage. However, the numerical model allows a closer approximation to experimental results because of considering the mortar contribution in the post-cracking stage., This study has been partially financed by the “European Union – NextGenerationEU”, through the Margarita Salas program, from the Spanish Ministry of Universities. The materials support of Sika AG and Mapei Spain S.A. is acknowledged. Authors want to thanks the research project SEVERUS (RTI2018- 099589-B-I00) of the Spanish Research Agency. Third author is a Serra Húnter Fellow., Peer Reviewed, Postprint (author's final draft)

Failure in fiber-reinforced composites is a complex phenomenon where different damage mechanisms interact and evolve through various scales. Micro-mechanical analysis using the finite element method has become an important alternative to study such failure phenomena and their interactions, by modeling explicitly the fiber, matrix, and fiber–matrix interface. In this work, the predictive capabilities of the finite element method together with the Phase-Field (PF) method for fracture has been assessed. The study compares different PF formulations, energy splits and numerical parameters, using Representative Volume Elements (RVEs) of different sizes, fiber distributions and with different Boundary Conditions (BCs). It is found that even though good approximations can be obtained and meso-scale failure envelopes for transverse loading generated, these are highly dependent on the modeling assumptions and PF parameters. The AT2 formulation combined with Amor’s energy split provides the best predictions when compared with an analytical failure surface. The best fit is found for transverse shear-dominated loading, while larger differences are found for compressive loading, whose strength predictions are strongly affected by the PF formulations and energy splits. It is demonstrated that meso-scale strength is conditioned by interface properties as interface damage is the dominant failure initiation mechanism under tensile-dominated loading. On the other hand, PF parameters have a stronger influence on compressive-dominated loading. Finally, it is shown that assuming a perfect fiber–matrix interface has a strong effect on the expected meso-scale strength, as failure is markedly delayed. Accordingly, based on the present results, especial care should be taken in properly assessing all the variables involved in the modeling methodology to draw conclusions from computational micro-mechanical analyses based on the PF approach., Postprint (published version)