Recursos de colección

Archivo Digital UPM (122.777 recursos)

This is an institutional repository providing access to the research output of the institution. Primarily contains thesis.

Materia = Materiales

Mostrando recursos 1 - 20 de 89

  1. Numerical simulation of the transition from densely distributed to localized cracking.

    Planas Rosselló, Jaime; Sancho Aznal, José María; Sanz Merino, Beatriz; Fathy Abdelaziz, Adel Mohamed; Aranguren, A.; Gálvez Ruiz, Jaime; Cendón Franco, David Ángel
    8th International Conference on Fracture Mechanics of Concrete and Concrete Structures (FraMCoS8).

  2. New designs of the ceramic bricks of horizontal hexagonal hollow

    Corbella Ribes, David; Fernández Martínez, Francisco; Hernandez Olivares, Francisco; Armisén Bobo, Pedro
    This article is intended to state that Technical Drawing is a multiple tool of expression and communication essential to develop inquiry processes, the scientifically basis and comprehension of drawings and technological designs that can be manufactured. We demonstrate graphically and analytically that spatial vision and graphic thinking allow us to identify graphically real life problems, develop proposals of solutions to be analysed from different points of view, plan and develop the project, provide information needed to make decisions on objects and technological processes. From the knowledge of Technical Drawing and CAD tools we have developed graphic analyses to improve and...

  3. The Cohesive Crack Model Applied To Notched PMMA Specimens Obeying a Non Linear Behaviour Under Torsion Loading

    Cendón Franco, David Ángel; Berto, F.; Lazzarin, P.; Elices Calafat, Manuel
    This article presents a new material model developed with the aim of analyzing failure of blunt notched components made of nonlinear brittle materials. The model, which combines the cohesive crack model with Hencky's theory of total deformations, is used to simulate an experimental benchmark carried out previously by the authors. Such combination is achieved through the embedded crack approach concept. In spite of the unavailability of precise material data, the numerical predictions obtained show good agreement with the experimental results.

  4. Impact Behavior of Hybrid Glass/Carbon Epoxy Composites

    Pérez Martín, Maria Jesus; Enfedaque Díaz, Alejandro; Dickson, William; Galvez Diaz-Rubio, Francisco
    The high velocity impact performance in hybrid woven carbon and S2 and E glass fabric laminates manufactured by resin transfer molding (RTM) was studied. Specimens with different thicknesses and glass-fiber content were tested against 5.5 mm spherical projectiles with impact velocities ranging from 300 to 700 m/s to obtain the ballistic limit. The resulting deformation and fracture micromechanisms were studied. Several impacts were performed on the same specimens to identify the multihit behavior of such laminates. The results of the fracture analysis, in conjunction with those of the impact tests, were used to describe the role played by glass-fiber hybridization on the...

  5. Experimental and numerical analysis of concrete Slabs subjected to Blast

    Cendón Franco, David Ángel; Morales Alonso, Gustavo; Galvez Diaz-Rubio, Francisco; Oña, M.; Sanchez Galvez, Vicente
    This paper summarizes the research activities focused on the behaviour of concrete and concrete structures subjected to blast loading carried out by the Department of Materials Science of the Technical University of Madrid (PUM). These activities comprise the design and construction of a test bench that allows for testing up to four planar concrete specimens with one single explosion, the study of the performance of different protection concepts for concrete structures and, finally, the development of a numerical model for the simulation of concrete structural elements subjected to blast. Up to date 6 different types of concrete have been studied, from plain normal strength concrete, to high...

  6. Modelling of chloride transport in non-saturated concrete : from microscale to macroscale

    Fenaux, Michiel; Reyes Pozo, Encarnación; Moragues Terrades, Amparo; Gálvez Ruiz, Jaime
    A model for chloride transport in concrete is proposed. The model accounts for transport several transport mechanisms such as diffusion, advection, migration, etc. This work shows the chloride transport equations at the macroscopic scale in non-saturated concrete. The equations involve diffusion, migration, capillary suction, chloride combination and precipitation mechanisms. The material is assumed to be infinitely rigid, though the porosity can change under influence of chloride binding and precipitation. The involved microscopic and macroscopic properties of the materials are measured by standardized methods. The variables which must be imposed on the boundaries are temperature, relative humidity and chloride concentration. The output...

  7. Experimental validation of a fracture model for pearlitic steel bars based on the cohesive zone model

    Suárez Guerra, Fernando; Gálvez Ruiz, Jaime; Atienza Riera, José Miguel; Cendón Franco, David Ángel; Elices Calafat, Manuel
    Congreso internacional celebrado en Praga sobre modelos numéricos de fractura en el campo de la ciencia de materiales y estructuras.

  8. An embedded cohesive crack model for finite element analysis of quasi-brittle materials

    Gálvez Ruiz, Jaime; Planas Rosselló, Jaime; Sancho Aznal, José María; Reyes Pozo, Encarnación; Cendón Franco, David Ángel; Casati Calzada, María Jesús
    This paper presents a numerical implementation of the cohesive crack model for the anal-ysis of quasibrittle materials based on the strong discontinuity approach in the framework of the finite element method. A simple central force model is used for the stress versus crack opening curve. The additional degrees of freedom defining the crack opening are determined at the crack level, thus avoiding the need for performing a static condensation at the element level. The need for a tracking algorithm is avoided by using a consistent pro-cedure for the selection of the separated nodes. Such a model is then implemented into...

  9. Fracture behaviour of notched round bars made of PMMA subjected to torsion at -60 °C

    Berto, F.; Cendón Franco, David Ángel; Lazzarin, P.; Elices Calafat, Manuel
    This paper presents seventy new experimental results from PMMA notched specimens tested under torsion at 60 C. The notch root radius ranges from 0.025 to 7.0 mm. At this temperature the non-linear effects previously observed on specimens of the same material tested at room temperature strongly reduce. The averaged value of the strain energy density over a control volume is used to assess the critical loads to failure. The radius of the control volume and the critical strain energy density are evaluated a priori by using in combination the mode III critical stress intensity factor from cracked-like specimens and the critical stress to failure detected from semicircular notches...

  10. Los materiales estructurales en los edificios de gran altura

    Fernandez Gomez, Jaime Antonio; Fernández-Ordóñez Hernández, David
    En este artículo se analiza el empleo de los diferentes materiales estructurales en la construcción de los edificios de gran altura. Se realiza un repaso histórico, desde el empleo de la fábrica resistente y los logros conseguidos con ella, hasta las tendencias más actuales. El predominio de la estructura metálica durante más de 50 años se ha visto abandonado con el empleo y la utilización de hormigones de alta resistencia. Otros dos hormigones especiales tienen su utilización: los hormigones autocompactantes, para hormigonar zonas muy congestionadas de armaduras, y los hormigones ligeros, para utilizar en la estructura horizontal y disminuir las...

  11. Modelo de comportamiento plástico y rotura en aleaciones de solidificación direccional

    Erice Echávarri, Borja; Pérez Martín, Maria Jesus; Cendón Franco, David Ángel; Galvez Diaz-Rubio, Francisco
    Esta investigación presenta un modelo de material para aleaciones de solidificación direccional que poseen un comportamiento mecánico transversalmente isótropo. Se han realizado una serie de ensayos de tracción sobre probetas cilíndricas a varias velocidades de deformación y a varias temperaturas sobre la superaleación de base níquel de solidificación direccional MAR-M 247 con objeto de conocer su comportamiento mecánico. Los ensayos se realizaron sobre probetas cilíndricas cuya dirección longitudinal forma 0º y 90º con la de la orientación de crecimiento de los granos. Para representar el comportamiento plástico anisótropo se ha formulado una función de plastificación de forma no cuadrática basada...

  12. Aporte martensíticos en la soldadura de aceros 9%Cr

    Oñoro Lopez, Javier; Portolés García, Antonio; Ibars Almonacil, Jose Ramón
    Los aceros 9% en cromo son utilizados en plantas de producción de energía eléctrica debido a su elevada resistencia a la corrosión, buenas propiedades mecánicas y resistencia a la termofluencia. Estos aceros presentan una estructura completamente martensítica. Sin embargo, la realización de uniones soldadas los hace susceptibles a la aparición en la zona fundida de ferrita delta, que reduce sus propiedades de termofluencia y tenacidad. Este trabajo analiza la microestructura del metal de aporte producido durante la soldadura manual con electrodo consumible (SMAW) utilizando aportes con diferentes composiciones en cromo y otros elementos de aleación como molibdeno, wolframio, cobre y...

  13. Detailed damage mechanisms assessment in composite materials by means of X-ray tomography

    Sket, Federico; Enfedaque Díaz, Alejandro; Alton, C.; Sádaba, Sergio; Molina Aldareguía, Jon M.; González Martínez, Carlos Daniel; Llorca Martinez, Francisco Javier
    This research focused on the evaluation of damage formation on ±45º carbon fiber laminates subjected to tensile tests. The damage was evaluated by means of X-ray tomography. A high density of cracks developed during the plateau of the stress-strain curve and were qualitatively analyzed, showing that the inner plies eventually developed a higher crack concentration than the outer plies. Delamination started to occur in the outermost ply interface when the slope after the plateau of the stress-strain curve began to increase.

  14. An analytical model for simulating the bond of prestressed concrete during the prestressed force release

    Benitez Baena, Jose Maria; Gálvez Ruiz, Jaime
    A bond analytical model is proposed in this paper. The model is capable of reproducing the bond stress developed between the steel and concrete, in precast prestressed elements, during the entire process of prestressing force release. The bond stress developed in the transmission zone, where the bond stress is not constant, is also obtained. The steel and concrete stresses as well as the slip between both materials can be also estimated by means of the relation established in the model between these parameters and the bond stress. The model is validated with the results of a series of tests, considering...

  15. Cohesive-frictional modelling of bond and splitting action of prestressing wire

    Benitez Baena, Jose Maria; Gálvez Ruiz, Jaime; Cendón Franco, David Ángel; Casati Calzada, María Jesús
    This work shows a numerical procedure for bond between indented wires and concrete, and the coupled splitting of the concrete. The bond model is an interface, non-associative, plasticity model. It is coupled with a cohesive fracture model for concrete to take into account the splitting of such concrete. The radial component of the prestressing force, increased by Poisson’s effect, may split the surrounding concrete, decreasing the wire confinement and diminishing the bonding. The combined action of the bond and the splitting is studied with the proposed model. The results of the numerical model are compared with the results of a...

  16. Techniques to accelerate convergence of stress-controlled molecular dynamics simulations of dislocation motion

    Cereceda, D.; Perlado Martín, José Manuel; Marian, Jaime
    Dislocation mobility —the relation between applied stress and dislocation velocity—is an important property to model the mechanical behavior of structural materials. These mobilities reflect the interaction between the dislocation core and the host lattice and, thus, atomistic resolution is required to capture its details. Because the mobility function is multiparametric, its computation is often highly demanding in terms of computational requirements. Optimizing how tractions are applied can be greatly advantageous in accelerating convergence and reducing the overall computational cost of the simulations. In this paper we perform molecular dynamics simulations of ½ 〈1 1 1〉 screw dislocation motion in tungsten...

  17. Conceptual design of the liquid metal laboratory of the TECHNOFUSION facility

    Abánades Velasco, Alberto; García, A.; Casal, N.; Perlado Martín, José Manuel; Ibarra, A.
    The application of liquid metal technology in fusion devices requires R&D related to many phenomena: interaction between liquid metals and structural material as corrosion, erosion and passivation techniques; magneto-hydrodynamics; free surface fluid-dynamics and any other physical aspect that will be needed for their safe reliable operation. In particular, there is a significant shortage of experimental facilities dedicated to the development of the lithium technology. In the framework of the TECHNOFUSION project, an experimental laboratory devoted to the lithium technology development is proposed, in order to shed some light in the path to IFMIF and the design of chamber's first wall...

  18. Variación de la energía de fractura del hormigón debido a la acción de los ciclos hielo-deshielo

    Enfedaque Díaz, Alejandro; Romero Mendoza, Héctor Leonardo; Gálvez Ruiz, Jaime
    El aumento de la vida útil de las estructuras de hormigón en la normativa europea y española ha hecho que la durabilidad del hormigón sea muy importante en el proyecto y construcción de las obras civiles. El deterioro del hormigón cuando está sometido a ciclos hielo-deshielo se mide empleando normas que no evalúan el deterioro de las propiedades mecánicas del hormigón. En este trabajo se ha diseñado una campaña experimental en la que se mide la energía de fractura de un hormigón convencional después de someterlo a 4, 14 y 28 ciclos hielo deshielo, siguiendo la norma UNE-CEN/TS 12390-9, y se compara con muestras...

  19. Análisis de metodologías para la medida de la resistencia a tracción por spalling

    Pérez Martín, Maria Jesus; Erice Echávarri, Borja; Cendón Franco, David Ángel; Galvez Diaz-Rubio, Francisco
    En el presente trabajo se presenta un estudio teórico y experimental de la determinación de la resistencia a tracción de materiales frágiles a partir de la técnica experimental de spalling. Se utilizan diferentes metodologías propuestas por varios autores para determinar la resistencia a tracción por spalling y se lleva a cabo un estudio mediante simulaciones numéricas de las diversas variables que influyen en este tipo de ensayos. Además, se realiza una campaña experimental de ensayos a una alúmina del 99,5% de pureza cuyos resultados son utilizados para la determinación de la resistencia a tracción de este material a partir de tres métodos diferentes propuestos por...

  20. Morteros acumuladores con parafinas microencapsuladas para el aprovechamiento de la energía solar en suelos radiantes

    Zetola Vargas, Vicente Andrés
    Esta Tesis plantea la pregunta de si el uso de morteros con parafinas microencapsuladas combinado con colectores solares térmicos puede reducir el consumo de energías convencionales, en un sistema tradicional de suelo radiante. Se pretende contribuir al conocimiento acerca del efecto que produce en el edificio, el calor latente acumulado en suelos radiantes, utilizando morteros de cemento Portland con material de cambio de fase (PCM), en conjunto con la energía solar. Para cumplir con este propósito, la investigación se desarrolla considerando diversos aspectos. En primer lugar, se revisa y analiza la documentación disponible en la actualidad, de almacenamiento de energía...

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