Artículos (Mecánica de Medios Continuos y Teoría de Estructuras)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/11397

Examinar

Mostrando 1 - 20 de 517

Crack bridging using linear elastic spring distribution with power-law variation of stiffness
(Elsevier, 2026-10) Ambikakumari Sanalkumar, Karthink; Mantic, Vladislav; Paggi, Marco; Mecánica de Medios Continuos y Teoría de Estructuras; Ministerio de Ciencia e Innovación (MICIN). España; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); European Union (UE). H2020
This article establishes a theoretical foundation and provides numerical evidence for a novel computational approach to simulate crack nucleation and propagation by finite crack advances within the framework of the coupled stress and energy criterion (CC) of finite fracture mechanics (FFM). The key innovation lies in bridging prospective crack paths, predicted by the stress criterion of CC, using a suitable Winkler-type continuous linear-elastic spring distribution. This allows a damage variable to be defined along these prospective finite crack paths, here called fictitious cracks. The effect of the spring stiffness variation on the elastic solution near a fictitious crack is analysed, focusing on how a power-law variation in spring stiffness affects the fictitious-crack tip stress singularity. Power-law variations of spring stiffness that eliminate this fictitious singularity are identified. Such a damageable spring distribution along the fictitious crack enables the seamless application of the energy criterion of CC to modelling virtual crack propagation through the progressive deactivation of springs within the bridged zone. Numerical tests show the effect of the power-law exponent of spring stiffness variation on both the stress state at the fictitious crack and on the energy release rate (ERR) calculated at the virtual-crack tip. Consequently, an optimal power law is proposed for modelling virtual crack propagation that successfully balances the elimination of the fictitious-crack tip singularity against the computational overhead associated with highly stiff spring distributions to achieve accurate ERR values. Finally, a new formulation of the path-independent J-integral is derived for a crack along a spring interface with varying stiffnesses.
Maximum vertical acceleration patterns in skewed multi-span railway bridges under increasing operational speeds
(Springer, 2026-07) Sánchez-Quesada, Juan Carlos; Moliner, Emma; Galvín, Pedro; Martínez-Rodrigo, María Dolores; Mecánica de Medios Continuos y Teoría de Estructuras; Universitat Jaume I; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Junta de Andalucía; European Union (UE)
This study investigates maximum vertical acceleration patterns in highly skewed, multi-span railway bridges, focusing on Serviceability Limit State (SLS) performance under increasing operational speeds. A 3D finite element model of a representative Spanish high-speed girder bridge is employed, explicitly incorporating the ballasted track and weak coupling between spans. The dynamic response is assessed using three train excitation models of increasing complexity: the simple moving load model (TLM), a vehicle-bridge interaction (VBI) model, and the latter incorporating track irregularities (VBI-η). The influence of deck skewness, modal participation, and ballast degradation at the simply-supported span interfaces is examined, along with a comparison to simplified analyses following code provisions. Quantitative results demonstrate that increasing deck skewness, from 90º to 134º, significantly reduces vertical accelerations by raising the first longitudinal bending and the first torsion frequencies, thus shifting prominent resonances outside the speed range of interest. While vehicle-bridge interaction (VBI) generally reduces accelerations at high speeds, track irregularities (VBI-η) can notably influence the maximum response depending on the speed window. The weak coupling between simply-supported spans affects spatial acceleration distribution, with maximum responses increasing near the supports. Additionally, localized ballast degradation at span interfaces impacts local peak accelerations. Comparisons show that code-based simplified models consistently overestimate accelerations above 300 km/h. These findings provide critical data for SLS compliance and speed upgrade assessments in multi-span skewed bridges.
Autoclave curing of nanosilica-modified ultra-high-performance concrete matrix: microstructural development, mechanical performance and fracture behaviour
(Elsevier, 2026-09) Ruiz Martínez, Jaime D.; Ríos Jiménez, José David; Carrasco Carrasco, Carlos Jesús; Luna Galiano, Yolanda; Cifuentes-Bulté, Héctor; Leiva Fernández, Carlos; Ingeniería Química y Ambiental; Mecánica de Medios Continuos y Teoría de Estructuras; Ministerio de Ciencia, Innovación y Universidades (MICIU). España
This study investigates the combined effect of nanosilica incorporation and autoclave curing on the hydration behaviour, microstructural development, and mechanical performance of ultra-high-performance concrete. The investigated material corresponds to a non-fibre UHPC matrix specifically designed for subsequent fibre reinforcement applications. Mixtures containing 0–7.5 wt% NS were subjected to standard curing and autoclave curing, and were characterised by X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and mercury intrusion porosimetry. XRD results show that nanosilica addition under standard curing increases the amorphous content due to accelerated clinker hydration and enhanced pozzolanic activity. In contrast, autoclave curing promotes the transformation of amorphous or weakly crystalline calcium silicate hydrate into thermodynamically stable and highly ordered tobermorite. Under autoclave curing conditions, nanosilica provides a highly reactive source of SiO₂, facilitating portlandite consumption and the crystallization of stable calcium silicate hydrates. Scanning Electron Microscopy observations corroborate these findings, revealing a transition from dense but disordered gel-like hydration products in standard curing mixtures to well-defined crystalline morphologies in autoclave treated specimens. TGA results further support the mineralogical trends identified by XRD, with nanosilica and autoclave modified mixtures exhibiting reduced mass losses associated with portlandite dihydroxylation. Porosimetry analysis indicates that moderate nanosilica dosages refine the pore structure. Overall, the synergistic use of nanosilica (3.5 wt%) and autoclave results in a refined and stabilized microstructure, which explains the observed improvement in the mechanical performance (average increases of 16% in compressive strength and 51% in tensile strength) of ultra high-performance concrete. Therefore, the reported fracture properties correspond to the matrix behaviour and do not include fibre-bridging effects typically observed in fibre-reinforced UHPC systems.
A natural programmable metamaterial controls 3D curvature of compound eyes
(Nature, 2026-06-30) Garrido García, Juan; Walther, Rhian F.; Torres-Tirado, Jesús; Andrés San Román, Jesús Ángel; Sanz Herrera, José Antonio; Pichaud, Franck; Casares, Fernando; Escudero Cuadrado, Luis María; Biología Celular; Mecánica de Medios Continuos y Teoría de Estructuras; Matemática Aplicada I; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; European Union (UE)
Panoramic vision of the convex compound eyes, common to insects and crustaceans, relies on micrometer-scale curvature variations. These variations generate specialized visual zones adapted to specific tasks, including detecting prey, mates, or predators. However, how such fine-scale curvature is encoded during development remains unknown. We find in Drosophila melanogaster that the basal surface of the developing retina is organized as a supracellular triangular mesh where the size of these triangles is distributed in a speciesspecific 2D pattern. Functional experiments using genetic perturbations, together with computational modeling, support the notion that this pattern guides adult eye local curvature. A similar pattern in the Drosophilamauritania developing retina indicates an evolutionary conservation of this mechanism. Our findings identify a mechanism of morphogenesis where fine-scale 3D curvature is programmed in the 2D patterning of a tissue with metamaterial properties. This mechanism provides a framework for designing shapeprogrammable 3D biological surfaces, with broad implications from synthetic morphogenesis to clinical applications.
Process‐induced anisotropy and fracture behavior of pellet‐3D printed PLA and PLA/flax biocomposites
(Wiley, 2026) Fernández Ancio, Fernando; Távara Mendoza, Luis Arístides; Marques Ferreira, Luis Miguel; Mecánica de Medios Continuos y Teoría de Estructuras; Ministerio de Ciencia e Innovación (MICIN). España; Ministerio de Ciencia, Innovación y Universidades (MICIU). España
Fused granular fabrication (FGF) enables cost-effective, large-scale polymer additive manufacturing; however, the mechanical behavior and fracture response of pellet extruded parts, particularly for natural-fiber composites, remain insufficiently characterized. This study evaluates the tensile response and fracture mechanisms of neat polylactic acid (PLA) and flax fiber-reinforced PLA (PLA/Flax) produced by FGF. Two hundred specimens are tested to quantify the influence of raster orientation and layer height on process-induced anisotropy. Tensile strength, elastic modulus, and density are measured, utilizing density-normalized metrics to reduce scatter, while fracture surfaces are analyzed by 3D optical profilometry. FGF-processed PLA reaches tensile strengths up to 59.5 MPa for a 0° raster orientation, whereas PLA/Flax achieves up to 45.82 MPa. Both materials present reduced elastic stiffness, with moduli approximately 40%–50% lower than common reference values. Reducing the layer height generally improves the mechanical performance and reduces the orientation sensitivity but increases the printing time and production cost. Profilometry confirms that anisotropy is governed by bead orientation and bonding quality. A reduction of approximately 46% in the average fracture surface roughness of representative PLA/Flax composite specimens was observed as layer height decreased, correlating with an increase in density-normalized tensile strength. These results provide practical guidance for selecting raster strategies to balance mechanical performance with manufacturing efficiency in pellet-based printing.
Impact of microstructural alterations to collagen networks on their mechanical behavior: a fiber in silico study of the articular cartilage surface
(Elsevier, 2026-10-01) Núñez Ortega, Elías; Sanz Herrera, José Antonio; Gaffney, Eamonn A.; Brown, Cameron P.; Reina Romo, Esther; Mecánica de Medios Continuos y Teoría de Estructuras; Ingeniería Mecánica y Fabricación; TEP245: Ingeniería de las Estructuras; TEP111: Ingeniería Mecánica
Background The collagen fibril network is a primary structural component of articular cartilage, ensuring its mechanical integrity; however, during osteoarthritis, this network undergoes pronounced structural changes. Hence, this in silico study investigates the non-linear mechanical behavior of collagen fibril networks representing the superficial zone of cartilage, examining normal and osteoarthritic conditions. Methods A previously validated in silico multiscale three-dimensional fiber network model has been extended by incorporating fibril interconnections (crosslinks) to represent the collagen network. This was first analyzed under normal conditions, followed by systematic modifications of key parameters—fibril Young’s modulus, crosslink density, and fibril orientation—to simulate degenerative microstructural changes characteristic of osteoarthritic cartilage in the superficial zone. Subsequently, computational transverse tensile tests, with uniaxial tension applied perpendicular to the preferential fibril orientation, were conducted to evaluate network integrity. These simulations predicted macroscopic mechanical responses, including energy and stress distributions in fibrils and crosslinks, providing insight into the transverse mechanical behavior of the collagen network under normal and pathological conditions. Results In the normal configuration, fibril interconnections appear to contribute to a more linear macroscopic mechanical response. Axial and bending energies are comparable in fibrils, and a limited set of fibrils and crosslinks act as stress concentrators. For degenerated configurations, stresses and energies increase significantly when fibrils are close to randomly oriented. Moreover, a case of mechanical compensation is found, where reduced interconnectivity does not decrease network stiffness after loading. Conclusions The proposed framework provides a virtual platform for investigating the mechanical behavior of normal and degenerated articular cartilage based on collagen microstructure. This may be combined with microstructural information from medical imaging to enable quantitative in silico explorations of how collagen network alterations influence tissue-scale mechanics.
Non-destructive assessment of fire-damaged RC columns by experimental modal analysis and sonic testing development, validation and application to real cases
(MDPI, 2026-05-28) Garduño Ferreras, Carlos; Compán Cardiel, Víctor Jesús; Sáez Pérez, Andrés; Pachón García, Pablo; Estructuras de Edificación e Ingeniería del Terreno; Mecánica de Medios Continuos y Teoría de Estructuras; TEP245: Ingeniería de las Estructuras
Post-fire evaluation of reinforced concrete (RC) columns in existing buildings demands reliable non-destructive methods capable of quantifying stiffness loss, identifying damage patterns, and supporting decisions on repair or replacement. This study develops and validates a dynamic NDT methodology that integrates Experimental Modal Analysis (EMA) and sonic testing (ST) based on elastic wave propagation to characterise the mechanical condition of fire-damaged RC columns. The procedure combines global dynamic indicators (natural frequencies and mode shapes) with local measurements of the dynamic Young’s modulus along the column height. A numerical finite element (FE) model is employed to validate the sensitivity and consistency of the proposed dynamic indicators under controlled degradation scenarios. After validation, the methodology is applied to two real fire events affecting basement columns in residential buildings. In the first case, several columns exhibit significant stiffness reductions, with pronounced modulus losses in the most exposed regions, leading to the recommendation of comprehensive strengthening measures. In the second case, results show minimal variations in most elements, allowing targeted intervention on a single moderately affected column. The study demonstrates that the combined EMA–ST approach provides a robust and cost-efficient basis for diagnosing fire-exposed RC columns and for guiding post-fire structural decision-making in practice.
High-resolution depth profiling of residual stresses in PVD coatings on additively manufactured polymers via FIB-DIC and eigenstrain theory
(MDPI, 2026-03-17) Rodríguez Mariscal, José Daniel; Srivastava, Karuna; Romero Ocaña, Ismael; Escobar-Galindo, Ramón; Bernasconi, Andrea; Hernández-Saz, Jesús; Mecánica de Medios Continuos y Teoría de Estructuras; Física Aplicada I; Ingeniería y Ciencia de los Materiales y del Transporte; Junta de Andalucía; TEP973: Tecnología de Polvos y Corrosión
The synergy between additively manufactured (AM) polymers and functional PVD coatings is crucial for advanced applications, yet the reliability of these hybrid systems is dictated by the residual stresses induced during deposition. This work presents the first in-depth, nanoscale profiling of residual stresses in Ti6Al4V and SS316 coatings on 3D-printed Acrylonitrile Styrene Acrylate (ASA) and Silicon (Si) substrates. A cutting-edge methodology combining Focused Ion Beam (FIB) milling with Digital Image Correlation (DIC), rigorously interpreted through the non-integral eigenstrain theory, is employed. Our findings reveal a consistent pattern of compressive stresses near the coating surface but expose a significant tensile stress peak at the coating-substrate interface, a feature not observed on reference silicon substrates. High-resolution electron microscopy and elemental analysis suggest that this stress concentration is associated with the presence of a thin, brittle oxide interlayer formed on the substrate surface. Furthermore, this study quantifies the dominant effect of the low-stiffness polymer substrate, which leads to a strain relief magnitude an order of magnitude higher than in rigid substrates. This work provides critical quantitative data on the failure-driving mechanisms in these emerging material systems and establishes a robust, optimized metrological protocol for their characterization.
Caracterización de la interfase en un ensayo a doble cortante pull-push usando un problema inverso y la Mecánica de la Fractura Finita
(Sociedad Española de Integridad Estructural. Grupo Español de Fractura SEIE-GEF, 2021-06) Muñoz-Reja Moreno, María del Mar; Távara Mendoza, Luis Arístides; Mantic, Vladislav; Mecánica de Medios Continuos y Teoría de Estructuras; Junta de Andalucía; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); European Commission. Fondo Social Europeo (FSO); Ministerio de Ciencia e Innovación (MICIN). España; TEP963: Ingeniería de Estructuras y Materiales; TEP131: Grupo de Elasticidad y Resistencia de Materiales
El criterio acoplado de la Mecanica de la Fractura Finita (CCFFM por sus siglas en inglés) aplicada al Modelo de Interfase Elástica-Lineal Frágil (LEBIM por sus siglas en inglés) ha mostrado ser una herramienta robusta y fiable para la caracterización del inicio y crecimiento de grietas de interfase a diferentes escalas. En el presente trabajo se usa este enfoque para analizar el comportamiento de las grietas que aparecen en la unión adhesiva presente entre una lamina de refuerzo de material compuesto y un bloque de hormigón en el ensayo de doble cortante pull-push. El estudio incluye el uso de la solución analítica de este problema (basada en un modelo de viga de Timoshenko) y resultados experimentales con diferentes configuraciones, para formular un problema inverso con la finalidad de obtener la resistencia y la tenacidad a la fractura necesarios para caracterizar la interfase. También se analizan modelos numéricos que incluyen las propiedades obtenidas en el problema inverso y que permiten estudiar no solo el inicio sino también la propagación de las grietas de interfase.
Implementación computacional del principio de mínima energía total sometido a una condicion de tensión (pmte-sc) del criterio acoplado de la mecánica de la fractura finita aplicado al LEBIM
(Sociedad Española de Integridad Estructural. Grupo Español de Fractura SEIE-GEF, 2022-06) Muñoz-Reja Moreno, María del Mar; Mantic, Vladislav; Távara Mendoza, Luis Arístides; Mecánica de Medios Continuos y Teoría de Estructuras; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Junta de Andalucía; European Commission. Fondo Social Europeo (FSO); TEP963: Ingeniería de Estructuras y Materiales; TEP131: Grupo de Elasticidad y Resistencia de Materiales
El Criterio Acoplado de la Mecánica de la Fractura Finita (CC-FFM) se ha aplicado tradicionalmente minimizando la carga necesaria para satisfacer los criterios de tensión y energía con respecto al tamaño de avance de la grieta, una variable desconocida a priori. Específicamente, este procedimiento minimiza la envolvente de las curvas de los criterios de tensión y energía. En general, este método conduce a un problema de minimización no suave y no convexo cuya solución es bastante fácil en el caso de una grieta que avanza en 2D, pero su implementación computacional general, fiable y robusta para muchas grietas que avanzan a la vez puede ser muy difícil de resolver. Con el objetivo de desarrollar una herramienta computacional general basada en el CC-FFM, una nueva metodología computacional basada en el Principio de Mínima Energía Total sujeto a una Condición de Tensión (PMTE-SC por sus siglas en inglés) fue propuesta por Mantic (2014), que incluye una representación discontinua de grietas y es básicamente equivalente a la formulación original de CC-FFM. En este trabajo se utiliza una herramienta computacional basada en el PMTE-SC implementada en el código FEM Abaqus® para predecir la aparición y propagación de grietas en las interfases tipo Winkler (muelles). El objetivo principal de este trabajo es comparar los resultados del código desarrollado con los resultados analíticos del ensayo de doble viga en voladizo (DCB por sus siglas en ingles).
Estudio comparativo de dos enfoques del criterio acoplado de la mecánica de la fractura finita
(Sociedad Española de Integridad Estructural. Grupo Español de Fractura SEIE-GEF, 2022-06) Muñoz-Reja Moreno, María del Mar; Mantic, Vladislav; Távara Mendoza, Luis Arístides; Mecánica de Medios Continuos y Teoría de Estructuras; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Junta de Andalucía; European Commission. Fondo Social Europeo (FSO); TEP963: Ingeniería de Estructuras y Materiales; TEP131: Grupo de Elasticidad y Resistencia de Materiales
El Criterio Acoplado de la Mecánica de la Fractura Finita (CC-FFM) se ha usado en trabajos previos, por los presentes autores, para predecir el inicio y crecimiento de grietas a lo largo de una interfase representada mediante el Modelo de Interfase Elástica-Lineal Frágil (LEBIM por sus siglas en inglés). El objetivo principal del presente trabajo es analizar la relación entre dos enfoques asociados al CC-FFM: (a) el método ampliamente usado basado en la búsqueda de la intersección de las curvas de criterios de tensión y energía, y (b) el nuevo Principio de Mínima Energía Total sujeto a una Condición de Tensión (PMTE-SC por sus siglas en inglés). Para ello, se comparan dos modelos analíticos del ensayo de doble viga en voladizo (DCB por sus siglas en ingles) basados en el modelo de vigas de Euler-Bernoulli. El ensayo DCB se estudia bajo control en carga por el método de las curvas y el PMTE-SC. Los resultados analíticos obtenidos prueban que las predicciones por el método de las curvas y el PMTE-SC son esencialmente idénticas.
Propagación dinámica de grietas de interfase usando el principio de mínima energía total sujeto a una condición de tensión (PMTE-SC)
(Sociedad Española de Integridad Estructural. Grupo Español de Fractura SEIE-GEF, 2024-06) Muñoz-Reja Moreno, María del Mar; Vodicka, Roman; Mantic, Vladislav; Távara Mendoza, Luis Arístides; Mecánica de Medios Continuos y Teoría de Estructuras; Ministerio de Ciencia e Innovación (MICIN). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); TEP963: Ingeniería de Estructuras y Materiales; TEP131: Grupo de Elasticidad y Resistencia de Materiales
El Criterio Acoplado de la Mecánica de Fractura Finita (CCFFM) se ha aplicado tradicionalmente minimizando la carga necesaria para satisfacer los criterios de tensión y energía con respecto al tamaño de avance de la grieta (que es una variable a priori desconocida). Recientemente varios autores han incluido la energía cinética en el balance energético entre el estado previo y final de la nueva superficie generada en el proceso de fractura. El objetivo de este trabajo es extender una herramienta computacional existente basada en el Principio de Mínima Energía Total sujeto a una condición de tensión (PMTE-SC), que ya ha mostrado ser equivalente a la formulación original del CCFFM, para poder predecir el inicio y propagación del daño en interfases bajo cargas dinámicas. En este código se utiliza un esquema escalonado de pasos de tiempo para resolver el problema de minimización de la energía total por separado, en términos de desplazamientos y de la variable de daño para cada paso de tiempo. En este trabajo se presenta una prueba de concepto del algoritmo con resultados preliminares satisfactorios.
Computational implementation of the minimization of the total energy with stress condition: versatile analysis of crack onset and propagation in complex scenarios
(Sociedad Española de Integridad Estructural. Grupo Español de Fractura SEIE-GEF, 2024-06) Ambikakumari Sanalkumar, Karthink; Mantic, Vladislav; Muñoz-Reja Moreno, María del Mar; Távara Mendoza, Luis Arístides; Mecánica de Medios Continuos y Teoría de Estructuras; European Union (UE). H2020; Ministerio de Ciencia e Innovación (MICIN). España; TEP131: Grupo de Elasticidad y Resistencia de Materiales; TEP963: Ingeniería de Estructuras y Materiales
El criterio acoplado en la Mecánica de Fractura Finita se utiliza para prever el inicio y progresión de grietas en materiales frágiles. Postula que las grietas se propagan en incrementos finitos, requiriendo el cumplimiento de criterios de energía y tensión. En el método numérico implementado utilizando una subrutina de usuario UINTER en ABAQUS, las caras de los avances finitos de las grietas que cumplen con el criterio tensional están conectadas por una serie continua de muelles elásticos lineales. Esta disposición permite la definición de una variable de daño a lo largo de estos posibles avances finitos de grietas. En consecuencia, la energía total, que incluye la energía potencial y disipada, presenta convexidad con respecto al campo de desplazamiento y la variable de daño por separado. Esta propiedad permite la aplicación del algoritmo de minimización alternante (AMA) para minimizar la energía total. Este enfoque, considerando pasos de carga, demuestra ser más adaptable que el criterio acoplado tradicional, presentando una herramienta prometedora para abordar problemas industriales complicados en el futuro. Se proporciona una demostración numérica que ilustra las predicciones precisas de la propagación de grietas. El ejemplo involucra grietas que impactan una interfaz curva débil, explorando posibilidades como penetración, cambio de dirección y desvíos de las grietas.
Predicción de múltiples despegues en las interfases fibra-matriz bajo carga transversal usando el principio de minimización de la energía total sujeto a una condición en tensiones
(Sociedad Española de Integridad Estructural. Grupo Español de Fractura SEIE-GEF, 2025-06) Pimentel Medina, José Miguel; Muñoz-Reja Moreno, María del Mar; Távara Mendoza, Luis Arístides; Mantic, Vladislav; Mecánica de Medios Continuos y Teoría de Estructuras; Ministerio de Ciencia e Innovación (MICIN). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); TEP963: Ingeniería de Estructuras y Materiales; TEP131: Grupo de Elasticidad y Resistencia de Materiales
En este trabajo se usa un algoritmo computacional basado en el Principio deMínima Energía Total sujeto a una Condición en Tensiones (PMTE-SC, por sus siglas en inglés) para estudiar uno de los principales mecanismos de fallo en materiales compuestos: el despegue a lo largo de las interfases fibra-matriz ante una carga transversal. Se hace especial énfasis en el carácter simétrico y no simétrico del inicio y propagación de los despegues en términos de los parámetros de fractura de la interfase. Los modelos considerados incluyen: una fibra de vidrio inmersa en una matriz epoxi y dos fibras de vidrio cercanas entre ellas en una matriz epoxi, donde la fibra secundaria está orientada a 0, 30, 45 y 90 grados respecto a la fibra de referencia. El presente algoritmo usa una formulación bidimensional en deformación plana en el código de elementos finitos Abaqus, junto con scripts de Python que implementan un incremento cuasi estático de la carga que minimiza el funcional de la energía total. El comportamiento de la interfase fibra-matriz se modela usando una distribución de muelles elástico-lineales con capacidad de daño mediante una subrutina de material para Abaqus. Los resultados numéricos indican un buen acuerdo con estudios analíticos anteriores, que además permiten predecir la carga de fallo y la morfología del inicio y propagación de los despegues asociados a dicha carga.
The legacy of José Domínguez: Contributions to boundary element formulations in fracture mechanics
(Elsevier, 2026) Sáez Pérez, Andrés; Rodríguez de Tembleque Solano, Luis; García Sánchez, Felipe; Buroni Cuneo, Federico Carlos; Mecánica de Medios Continuos y Teoría de Estructuras; Ingeniería Mecánica y Fabricación
This work reviews and critically assesses the scientific legacy of José Domínguez in the development of boundary element formulations for fracture mechanics. The review focuses on methodological advances that shaped the modern use of the boundary element method (BEM) for crack problems, with emphasis on: (i) crack-tip element technology – including singular quarter-point and discontinuous quarter-point elements – that enables direct extraction of fracture parameters from boundary integral equations; (ii) regularization procedures for singular and hypersingular kernels that preserve standard BEM infrastructure; and (iii) extensions from linear elastostatics to coupled-field solids and to dynamic fracture via frequency- and time-domain formulations. The scope is restricted to linear fracture formulations under the assumptions of pre-existing sharp cracks and small-scale yielding, both in classical elasticity and in linear coupled-field settings. The discussion covers quasi-static and dynamic fracture analyses, three-dimensional extensions, and the systematic generalization to anisotropic, piezoelectric, and magnetoelectroelastic solids, where multifield coupling introduces additional theoretical and numerical challenges. Rather than aiming at an exhaustive survey, the paper traces the coherent research line initiated by Domínguez and continued by his collaborators, highlighting how these contributions established a unified framework for fracture analysis that remains foundational in current boundary element research.
Análisis por elementos finitos del crecimiento de grietas en modo I+II en uniones adhesivas usando un nuevo elemento singular
(Sociedad Española de Integridad Estructural, 2025-09) Herrera Garrido, María Ángeles; Távara Mendoza, Luis Arístides; Muñoz-Reja Moreno, María del Mar; Mantic, Vladislav; Mecánica de Medios Continuos y Teoría de Estructuras; European Union (UE). H2020; Ministerio de Ciencia e Innovación (MICIN). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); TEP131: Grupo de Elasticidad y Resistencia de Materiales
Adhesive joints are increasingly used in a wide range of industries, requiring detailed analyses of crack growth. These studies often rely on finite element method (FEM) simulations, which face challenges such as logarithmic stress singularities at crack tips on Winkler-type spring interfaces. Addressing these singularities typically requires strong mesh refinement, resulting in high computational costs. This work proposes a novel finite element for plane fracture analysis in mode I+II, focusing on cracks along interfaces modeled by Winkler-type spring distributions. The element is triangular with 5 nodes obtained by collapsing a 6-node rectangular element. It incorporates the asymptotic elastic solution for logarithmic stress singularities, improving the accuracy of Energy Release Rate (ERR) calculations compared to standard finite elements. This approach achieves higher accuracy in simulations with the presence of cracks while substantially reducing computational costs. These results demonstrate the potential of the proposed element to enhance the efficiency and accuracy of fracture mechanics analyses in adhesive joints, making it a promising tool for addressing interface-related challenges in FEM.
Influence of Water Absorption on the Impact Response and Failure Mechanisms of 3D-Printed PLA-Based Honeycomb Sandwich Composite Structures
(Wiley, 2026-01) Nur Ainin, Faissal; Azaman, M.D.; Marques Ferreira, Luis Miguel; Coelho, Carlos A.C.P.; Abdul Majid, M.S.; Ridzuan, M.J.M.; Mecánica de Medios Continuos y Teoría de Estructuras
This study investigates the influence of water absorption on the impact response and failure mechanisms of 3D-printed sandwich composites with hexagonal honeycomb cores composed of polylactic acid (PLA)-based materials, focusing on the comparative performance of natural (PLA–Wood) and synthetic (PLA–Carbon) reinforcements in moisture-prone environments. The objective was to assess the effect of filler type on energy absorption, deformation, and failure progression after 30 days of water immersion under low-velocity impact testing. The results indicate that water absorption has a material-dependent impact on the mechanical performance. PLA–Wood exhibited the highest moisture uptake (21%), resulting in the greatest energy absorption (3.863 J) and end-displacement (11.211 mm) owing to filler swelling and interfacial weakening. PLA–Carbon exhibited moderate water uptake (11%) with comparable energy absorption (3.856 J) but reduced end-displacement (9.128 mm), indicating improved load transfer and stability. PLA demonstrated the lowest water uptake at 6% and energy absorption at 3.618 J, with minimal damage observed. Fourier-transform infrared spectroscopy (FTIR) confirmed hydrolytic degradation, whereas scanning electron microscopy (SEM) and optical imaging revealed interfacial debonding and microstructural deterioration. These findings offer engineers critical insights into filler–matrix interactions and inform the design of impact-resistant and moisture-tolerant composites for aerospace, marine, and other high-humidity structural applications.
Multi-Scale Characterization of PLA Composites With Natural-Based Reinforcements: From Filament to 3D-Printed Parts
(Wiley, 2026) Reis, Paulo Nobre Balbis; Távara Mendoza, Luis Arístides; Muñoz-Reja Moreno, María del Mar; Aranda Romero, María Teresa; Nur Ainin, Faissal; Azaman, M.D.; Marques Ferreira, Luis Miguel; Mecánica de Medios Continuos y Teoría de Estructuras; Ministerio de Ciencia e Innovación (MICIN). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Fundação para a Ciência e a Tecnologia. Portugal
To address plastic waste and agricultural residue underutilization, this study evaluates the thermal (DSC and FTIR), microstructural (SEM), and mechanical behavior of polylactic acid (PLA) reinforced with flax fibers and olive pit particles, processed by fused filament fabrication (FFF). The results show the FFF reduces neat PLA's tensile strength by 10.8% and its tensile modulus by 31.6%, primarily due to process-induced voids, poor interlayer bonding, and polymer degradation that affect load transfer. The incorporation of flax fibers and olive pit particles leads to a further decrease in mechanical performance, reducing tensile and bending strength by up to 37% and 39.6%, respectively. In flax fiber composites, this is mainly caused by fiber degradation, poor interfacial adhesion, and random dispersion, which limit load transfer efficiency. Similarly, while olive pit particles exhibit greater thermal stability, their hydrophobic nature restricts adhesion to the PLA matrix, resulting in insufficient stress transfer. Moreover, the composite parts present complex failure mechanisms, including fiber pull-out and crack deflection. In conclusion, the natural reinforcements reduce the PLA's mechanical performance and modify its fracture behavior. In its current form, they show potential for sustainable composites in non-structural applications where aesthetics and environmental factors are important. To expand their use into structural applications, future work should focus on improving filler-matrix compatibility, optimizing particle size, fiber content, and processing conditions.
Full-field elastic solution reconstruction of mechanical tests using a physics-based inverse method
(Elsevier, 2026-05) Sanz Herrera, José Antonio; Serna Moreno, M.C.; Horta Muñoz, S.; Chamorro Moreno, Rosario; Mecánica de Medios Continuos y Teoría de Estructuras; Ingeniería Mecánica y Fabricación; Ministerio de Ciencia e Innovación (MICIN). España; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER)
Accurate determination of the mechanical properties of materials is a technological necessity across a wide range of engineering applications. In this context, mixed numerical–experimental techniques aim to estimate anisotropic elastic constants by using measured displacement fields and loads as inputs. Although these methods seek to reduce the complexity of experimental campaigns, they still present some challenges. This paper introduces a novel inverse approach which addresses existing limitations by utilizing displacement and load data from a reduced region of the domain, thereby eliminating the need for a known distribution of boundary conditions. The developed algorithm was validated through two examples of application based on the Iosipescu test. In the first example, the approach demonstrated exceptional accuracy with synthetically generated data, achieving reconstruction errors of 0.55% and 1.49% for the elastic constants and strain field of a baseline case, respectively, even when a highly noisy input strain field is employed. Its practical viability was further confirmed in a second example using real test measurements. Beyond the recovery of elastic constants, the methodology also provides a physically consistent stress field across the full domain of the specimen, suggesting its broader utility for computing realistic stresses in structures from minimal data without pre-established deterministic hypotheses.
Simple finite element algorithm for solving antiplane problems with Gurtin–Murdoch material surfaces
(Elsevier, 2025-04) Herrera Garrido, María Ángeles; Mogilevskaya, Sofia G.; Mantic, Vladislav; Ingeniería y Ciencia de los Materiales y del Transporte; Mecánica de Medios Continuos y Teoría de Estructuras; European Union (UE). H2020; Ministerio de Ciencia e Innovación (MICIN). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); TEP131: Grupo de Elasticidad y Resistencia de Materiales
The finite element algorithm is developed to solve antiplane problems involving elastic domains whose boundaries or their parts are coated with thin and relatively stiff layers. These layers are modeled by the vanishing thickness Gurtin–Murdoch material surfaces that could be open or closed, and smooth or non-smooth. The governing equations for the problems are derived using variational arguments. The domains are discretized using triangular finite elements. In general, standard linear elements are used to approximate displacements in the domain. However, to capture the singular behavior of the elastic fields near the tips of the open Gurtin–Murdoch surfaces, a novel blended singular element is devised. Numerical examples are presented to demonstrate the accuracy and robustness of the algorithm developed.

Examinar

Envíos recientes