Graphic summary
  • Show / hide key
  • Information


Scientific and technological production
  •  

1 to 50 of 103 results
  • High temperature scratch testing of hard PVD coatings deposited on surface treated tool steel

     Pujante, Jaume; Vilaseca, Montserrat; Casellas, Daniel; Riera Colom, Maria Dolores
    Surface and coatings technology
    Vol. 254, p. 352-357
    DOI: 10.1016/j.surfcoat.2014.06.040
    Date of publication: 2014-09-15
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Scratch testing is one of the most usual characterisation techniques for systems with thin hard coatings. Scratch tests are performed at run at room temperature, due to the risk of degradation of the indenter diamond tip at high temperature and added test complexity. However, results obtained at room temperature may differ from the final system performance in high temperature applications, due to factors such as substrate thermal softening. In this work, a simple and a robust test for the mechanical characterisation of hard PVD coatings at high temperature and open atmosphere has been developed, based on a modification of the scratch test where the diamond tip is replaced by a WC indenter. The test has been used to evaluate the effect of temperature up to 500 °C on commercial PVD AlCrN coating deposited on tool steel subject to different surface treatments. Results show a decrease in the failure load Lc2 with increasing temperature, and a very noticeable effect of substrate nitriding.

  • Access to the full text
    Estudio de la resistencia a fatiga térmica en moldes de inyección de aluminio utilizando aceros de alta conductividad térmica  Open access

     Molas Busquets, Sílvia; Hamasaiid, Anwar; Llobet, Albert; Valls, Isaac; Casellas Padro, Daniel; Riera Colom, Maria Dolores
    Congreso Nacional de Tratamientos Térmicos y de Superficie
    p. 309-320
    Presentation's date: 2013-04-23
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    La mayoría de los mecanismos de fallo que determinan la durabilidad de un molde de inyección de aluminio a alta presión están relacionados con las solicitaciones termo-mecánicas de la superficie. En cada ciclo, la superficie de la herramienta está expuest a a elevadas variaciones de temperatura y cargas mecánicas que ocasionan la pérdida de propiedades superficiales (dureza, resistencia, etc.). La variación de las propiedades superficiales y las tensiones termo-mecánicas generadas en los ciclos de inyección inducen la aparición de grietas. A fin de retardar la aparición de estas grietas, se ha desarrollado una nueva generación de aceros de herramienta de trabajo en caliente denominados HTCS® (High Thermal Conductivity Steels) caracterizados por poseer elevados valores de difusividad térmica combinados con elevadas propiedades termo-mecánicas, comparados con los aceros de trabajo en caliente convencionales. Estas propiedades, sobre todo la difusividad térmica elevada, tienen su principal efecto en la reducción de las tensiones superficiales generadas en las herramientas debido a los gradientes térmicos durante el servicio, Esta reducción de tensiones se traduce en un aumento de la vida útil del molde de inyección. En este trabajo se evalúa el efecto de la conductividad térmica del acero de herramientas en la aparición y propagación de grietas por fatiga térmica . Para ello, se han fabricado dos moldes experimenta les de inyección de aluminio a alta presión con la misma geometría y dureza. Un molde se ha fabricado con acero de trabajo en caliente convencional (AISI Hll) y el otro molde con acero de alta conductividad térmica (HTCS®). Se ha realizado el seguimiento de la aparición y propagación de las grietas por fatiga térmica en los dos moldes durante el servicio. Para poder investigar y entender mejor la relación entre las diferencias térmicas y las tensiones superficiales generadas en los dos moldes experimenta les, se ha utilizado un modelo simple de Simulación por Elementos Finitos representativo de una sección del molde real.

  • Simulación de un tratamiento térmico mediante elementos finitos

     Giménez, Maria; Llobet, Albert; Riera Colom, Maria Dolores; Prado Pozuelo, Jose Manuel
    Congreso Nacional de Tratamientos Térmicos y de Superficie
    p. 147-158
    Presentation's date: 2013-04-22
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Access to the full text
    Sheet failure prediction during forming of advanced high strength steels  Open access

     Gutiérrez, D.; Hernández, R.; Riera Colom, Maria Dolores; Lara, Toni; Casellas, Daniel; Prado Pozuelo, Jose Manuel
    Forming Technology Forum
    p. 93-98
    Presentation's date: 2012-06-05
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    The automotive industry has increased significantly the use of advanced high strength steels (AHSS) in many structural components of vehicles, with the aim to reduce weight and also increase safety. The high resistance of these steels is accompanied by a decrease in formability, which makes simulation a requirement to adequately foresee the formability of a stretch formed component. For sheet metal forming, the conventional diagram based in strains, Forming Limit Diagrams (FLD), is often used as a failure criterion, but this approach is not effective when working with AHSS, due to the bigger effect produced by changes on strain paths than conventional steels. This work proposes the use a Forming Limit Stress Diagram (FLSD) based on the main stresses acting on the material. These FLSD has been obtained by the simulation of stretching test. To improve the results, the tensile test curve has been extended by using an optical measuring system and a subsequent adjustment of the stress-strain curve for the material. Finally, simulations and real parts behavior have been compared and the failure predictions models have been discussed.

  • Access to the full text
    Simulación del proceso de emisión acústica. Generación de ondas elásticas transitorias en un engranaje bajo tensión  Open access

     Cobo Molina, Raul; Rezano Inza, Tomás; Riera Colom, Maria Dolores; Romeral Martinez, Jose Luis
    Reunión de Usuarios de SIMULIA
    p. 1-11
    Presentation's date: 2012-11-12
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Con el objetivo de que el funcionamiento de una máquina sea el correcto es imperativo asegurar que existe un buen mantenimiento predictivo. Es conveniente tener un sistema inteligente y dispositivos capaces de detectar fallos en fases tempranas. Los fallos más comunes en máquinas industriales son todos aquellos relacionados con los sistemas de transmisión de potencia. La técnica de emisión acústica (EA) es el último enfoque para detectar e identificar defectos en rodamientos, cajas de cambio y uniones mecánicas. La emisión acústica (EA) es el fenómeno de generación de ondas elásticas transitorias en materiales bajo tensión. Cuando el material está sometido a un cierto nivel de tensión, una liberación rápida de energía de deformación tiene lugar en forma de ondas elásticas, las cuales pueden ser detectadas mediante transductores colocados en la pieza en cuestión. El objetivo de este trabajo es proporcionar una caracterización de las ondas elásticas que emanan de grietas localizadas entre el flanco y el valle de un engranaje. Las señales han sido registradas usando transductores colocados en la superficie del engranaje (a media distancia entre el eje y los dientes). El método de los elementos finitos ha sido utilizado para simular las ondas elásticas emitidas durante el crecimiento de las grietas. El modelo de simulación está basado en suposiciones elásticas y se ha llevado a cabo mediante Abaqus. Estos resultados han sido comparados con los resultados experimentales.

    In order to have a machine that functions well it is imperative to ensure that there is a good predictive maintenance. An intelligent system and devices able to detect the fault in its early stage is then convenient. The most common failures in industrial machines are those related to the power transmission systems. Acoustic Emission (AE) is the latest approach in detecting and identifying faults in bearings, gearboxes and mechanical couplings. Acoustic Emission (AE) is the phenomenon of transient elastic wave generation in materials under stress. When the material is subjected to stress at a certain level, a rapid release of strain energy takes place in the form of an elastic wave which can be detected by transducers placed on it. The objective of this work is to provide a characterization of elastic waves emanating from cracks located between the flank and the valley of a gear. The signals have been recorded using transducers attached to the surface of the gear (midway between the shaft and the teeth). FE modeling has been used to simulate the elastic waves emitted from fatigue crack growth. The model is based on linear elasticity assumptions and undertaken using Abaqus. These results have been compared with the experimental ones.

  • Stress corrosion cracking resistance in hot forming tools

     Gironés Molera, Anna; Molas i Busquets, Sílvia; Riera Colom, Maria Dolores; Casellas, Daniel
    International Tooling Conference
    Presentation's date: 2012-09-11
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Access to the full text
    Flow regime analyses during the filling stage in powder metallurgy processes: experimental study and numerical modelling  Open access

     Cante Teran, Juan Carlos; Riera Colom, Maria Dolores; Oliver Olivella, Fco. Javier; Prado Pozuelo, Jose Manuel
    Granular matter
    Vol. 13, num. 1, p. 79-92
    DOI: 10.1007/s10035-010-0225-4
    Date of publication: 2011-01
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Experimental and numerical studies of powder flow during the die filling stage in powder metallurgy cold compaction processes are presented. An experimental setting consisting of a horizontal pneumatically activated shoe, a vertical die and high-speed video system has been designed. The experiments show the existence of three flow regimes: continuous, transitory and discrete, which are identified in terms of the particle size, the morphology and the speed of the shoe. In the continuous regime the powder flows in a progressive manner but in the discrete one some perturbations appear as a consequence of a shear band formation that forms discrete avalanches. A numerical model, based on a ratedependent constitutive model, via a flow formulation, and in the framework of the particle finite element method (PFEM) is also proposed. For the purpose of this study, the use of the PFEM assumes that the powder can be modelled as a continuous medium. The model, provided with the corresponding characterisation of the parameters, is able to capture the two fundamental phenomena observed during the filling process: (1) the irreversibility of most of the deformation experienced by the material and (2) the quick dissipation of the potential gravitatory energy of the granular system through the inter-particle friction processes, modelled by the plastic dissipation associated with the material model. Experimental and numerical results have been compared in order to study the viability of the proposed model.

  • Stress corrosion cracking resistance in hot forming tools

     Gironés Molera, Anna; Molas i Busquets, Sílvia; Riera Colom, Maria Dolores; Casellas, Daniel
    European Corrosion Congres
    p. 604-
    Presentation's date: 2011-09-06
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Access to the full text
    FLSD as a good choice in sheet forming of AHSS  Open access

     Hernandez Rossi, Ricardo; Llobet Lorenzo, Alberto; Gómez, X.; Riera Colom, Maria Dolores
    SIMULIA Customer Conference
    p. 238-246
    Presentation's date: 2011-05-18
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    The automotive industry has increased significantly the use of advanced high strength steels (AHSS) in many structural components, with the aim to reduce weight and also to increase safety. The high resistance of these steels is accompanied by a decrease in formability, which makes simulation a requirement to adequately foresee the formability of a particular stretch formed component. This work shows that Abaqus can be used in the cold stamping calculations, by mainly estimating the occurrence of rupture and necking during forming. Formability studies usually use forming limit diagrams (FLD), based on stains, as a failure criterion, but this approach is not effective when working with AHSS. This work proposes the use a forming limit stress Diagram (FLSD) based on the main stresses acting on the material. A brief explanation of how to obtain these FLSD curves is presented, where ABAQUS also plays an important role. Finally, comparisons using simulations from AUTOFORM and real parts are shown and discussed. The comparison was performed using Abaqus CAE and Viewer as post-processing tools. A script allows reproducing the mesh generated by AUTOFORM, map the data and postprocess with the FLSD criterion. All the methodology presented uses ABAQUS as an integral tool, from the characterization of the material to the analysis of complex parts.

  • Young's modulus variation during unloading for a wide range of AHSS steel sheets

     Cobo Molina, Raul; Hernandez Rossi, Ricardo; Benito Paramo, Jose Antonio; Riera Colom, Maria Dolores
    International Deep Drawing Research Group
    p. 1-10
    Presentation's date: 2011-06-07
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • The elastic behaviour of non-sintered metal powder compacts

     Riera Colom, Maria Dolores; Prado Pozuelo, Jose Manuel
    Proceedings of the Institution of Mechanical Engineers. Part E, journal of process mechanical engineering
    Vol. 224, num. Special Issue, p. 195-201
    DOI: 10.1243/09544089JMPE375
    Date of publication: 2010
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • MEJORA DEL COMPORTAMIENTO A FATIGA Y DE LA CONFORMIBILIDAD DE ACEROS METAESTABLES MEDIENTE DISEÑO

     Prado Pozuelo, Jose Manuel; Calvo Muñoz, Jessica; Heredero Alari, Francisco; Riera Colom, Maria Dolores; Llanes Pitarch, Luis Miguel; Fargas Ribas, Gemma; Salán Ballesteros, Mª Núria; Mestra Rodríguez, Alvaro Miguel; Garcia Marro, Fernando; Zapata Dederlé, Ana Cristina; Mir Carbonell, Jordi; Botero Vega, Carlos Alberto; Mateo Garcia, Antonio Manuel
    Competitive project

     Share

  • Hard cutting of tailored hardened 22MnB5

     Laumann, Till; Picas Anfruns, Ingrid; Grané, Marc; Casellas Padro, Daniel; Riera Colom, Maria Dolores; Valls, Isaac
    International Deep Drawing Research Group
    p. 355-362
    Presentation's date: 2010-06-01
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Predicción del springback en el conformado asistido por láser de chapas de acero DP800 mediante simulación con Abaqus

     Cobo Molina, Raul; Brígido Belmonte, Albert; Benito Paramo, Jose Antonio; Romero, Pablo; Otero, Nerea; Riera Colom, Maria Dolores
    Congreso Nacional de Tratamientos Térmicos y de Superficie
    p. 85-96
    Presentation's date: 2010-10
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Simulación del proceso de generación de ultrasonidos mediante láser: detección, posicionamiento y medición de grietas o ranuras superficiales en régimen termolástico

     Cobo Molina, Raul; Riera Colom, Maria Dolores
    Reunión Nacional de Usuarios de SIMULIA
    p. 1-14
    Presentation's date: 2010-11
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Modelling and simulation of stamping of high strength steels

     Riera Colom, Maria Dolores; Prado Pozuelo, Jose Manuel
    NAFEMS Awareness Seminar
    p. 1-45
    Presentation's date: 2010-04-28
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • AUMENTO DE LA DUCTIBILIDAD EN FRIO DE MATERIALES METÁLICOS CON TAMAÑO DE GRANO NANOCRISTALINO Y ULTRAFINO

     Prado Pozuelo, Jose Manuel; Benito Paramo, Jose Antonio; Riera Colom, Maria Dolores; Llumà Fuentes, Jordi; Jorba Peiró, Jordi; Cabrera Marrero, Jose Maria
    Competitive project

     Share

  • PROCESAMIENTO, PROPIEDADES Y CARACTERÍSTICAS DE ACEROS DESTINADOS AL SECTOR ELECTRICO

     Benito Paramo, Jose Antonio; Prado Pozuelo, Jose Manuel; Calvo Muñoz, Jessica; Riera Colom, Maria Dolores; Suarez Fernandez, Lucia; Rodríguez Calvillo, Pablo; Cabrera Marrero, Jose Maria
    Competitive project

     Share

  • Simulation of hot stamping processes

     Riera Colom, Maria Dolores; Coussirat Nuñez, Miguel Gustavo; Guardo Zabaleta, Alfredo de Jesús; Valls, I; Casellas Padro, Daniel
    International Conference on Hot Sheet Metal Forming of High-Performance Steel
    p. 119-131
    Presentation's date: 2008-10
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Access to the full text
    De Bolonia (1088) a Bolonia (1988-2010). De la enseñanza basada en el conocimiento a la enseñanza basada en las habilidades  Open access

     Riera Colom, Maria Dolores; Prado Pozuelo, Jose Manuel
    Taller Iberoamericano de Educación en Ciencia e Ingeniería de Materiales
    p. 1-10
    Presentation's date: 2008-12-02
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    La humanidad está viviendo un período histórico de profundas transformaciones. La sociedad avanza a un ritmo muy superior al de sus propias estructuras, y la universidad reacciona por detrás de los acontecimientos. Se dice que la universidad está en crisis y no sólo de tipo financiero. En este trabajo se expone una breve historia de la universidad; se exponen sucintamente los distintos modelos a partir de los cuales se crean las universidades modernas y se plantean algunos de los aspectos fundamentales de la situación de la universidad actual debidos a la democratización y al cambio profundo, rápido y continuo del mercado laboral y, en general, de la sociedad. El proceso de Bolonia, a través del cual se define un Área de educación superior en Europa, está cargado de buenas intenciones y mejores palabras; pero, ¿serán todos los estamentos involucrados capaces de llevar a buen puerto una transformación tan intensa de la universidad?

  • Model input data - elastic properties

     Riera Colom, Maria Dolores; Prado Pozuelo, Jose Manuel; Doremus, Pierre
    DOI: 10.1007/978-1-84628-099-3_5
    Date of publication: 2008
    Book chapter

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Tribological approach of forming tool performance based on finite element modelling (FEM)

     Hernandez Rossi, Ricardo; Cruz, Marlon; Picas Anfruns, Ingrid; Riera Colom, Maria Dolores; Casellas Padro, Daniel
    International Symposium on Friction, Wear and Wear Prediction
    p. 33
    DOI: 10.1002/9783527628513.ch40
    Presentation's date: 2008-04-10
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Mechanical performance of tools in cold forming of high stregth steels

     Picas Anfruns, Ingrid; Casellas Padro, Daniel; Llobet Lorenzo, Alberto; Hernandez Rossi, Ricardo; Riera Colom, Maria Dolores; Valls, Isaac; Casas Aguirregomezcorta, Begoña
    International Conference on New Developments in Advanced High Strength Sheet Steels
    p. 391-400
    Presentation's date: 2008
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Study of the influence of the decrease of the apparent young's modulus during unloading in the springback prediction

     Cobo Molina, Raul; Hernandez Rossi, Ricardo; Benito Paramo, Jose Antonio; Casellas Padro, Daniel; Riera Colom, Maria Dolores
    International Deep Drawing Research Group
    p. 785-791
    Presentation's date: 2008-06-16
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Conformado en caliente de chapa de acero

     Riera Colom, Maria Dolores; Hernandez Rossi, Ricardo; Prado Pozuelo, Jose Manuel
    Congreso Nacional de Tratamientos Térmicos y de Superficie
    p. 91-99
    Presentation's date: 2008-03
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Fracture toughness characterization of advanced high strength steels by means of the essential work of fracture

     Llobet Lorenzo, Alberto; Casellas Padro, Daniel; Riera Colom, Maria Dolores; Prado Pozuelo, Jose Manuel
    International Conference on New Developments in Advanced High Strength Sheet Steels
    p. 315-323
    Presentation's date: 2008
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Fracture toughness cannot be readily measured in metal sheet because the small thickness in which they are used (1-3 mm). In this sense the essential work of fracture (EWF) has been successfully applied to determine fracture toughness in polymers films and many metal sheets. However, their information about the applicability of this methodology to AHSS is relatively scarce. In the present work the fracture toughness of some advanced high strength steel Dual Phase and drawing steel sheets has been measured by means of the EWF. The results show that AHSS steels with yield strength up to 800 MPa meet the requirements of the method, and therefore the values obtained for the EWF are valid. Thus, the EWF is postulated as methodology to evaluate the fracture toughness and can be used as a mechanical parameter to characterize the fracture behavior during crash of AHSS steel sheets

  • Manufacturing and full characterization of silicon carbide-based multi-sensor micro-probes for biomedical applications

     Gabriel, Gemma; Erill, I; Caro, J; Gomez, R; Riera Colom, Maria Dolores; Villa Millaruelo, Ricardo; Godignon, P
    Microelectronics journal
    Vol. 38, num. 3, p. 406-415
    DOI: 10.1016/j.mejo.2006.11.008
    Date of publication: 2007-03
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Semi-insulating silicon carbide (SiC) is a fully processable semiconductors substrate that is commonly used as an alternative to conventional silicon (Si) in high-power applications. Here we examine the feasibility of using SiC as a substrate for the development of minimally invasive multi-sensor micro-probes in the context of organ monitoring during transplantation. In particular, we make a thorough comparison of Si and SiC material mechanical and electrical properties, and we extend this analysis to life-like situations using completed devices. Our results show that SiC outperforms Si in all respects, with a four times higher modulus of rupture for SiC devices and a 10-fold increase in the frequency range for electrical measurements in SiC-based probes. These results suggest that SiC should be preferably used over Si in all biomedical applications in which device breakage must be avoided or very precise electrical measurements are required.

  • Access to the full text
    Evaluación del comportamiento a desgaste en aceros de herramienta: simulación por ordenador y verificación experimental  Open access

     Hernandez Rossi, Ricardo; Cruz, Marlon; Casellas Padro, Daniel; Riera Colom, Maria Dolores; Prado Pozuelo, Jose Manuel
    Anales de mecánica de la fractura
    Vol. 2, p. 619-623
    Date of publication: 2007
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    En el sector automovilístico se ha incrementado el uso de aceros de alta y muy alta resistencia para conformar piezas de carrocería. La utilización de estos nuevos aceros lleva asociada una problemática específica en la construcción de los útiles de conformado. El elevado límite elástico de estos aceros obliga a utilizar elevadas presiones de conformado, lo que provoca la aparición de roturas y desgaste prematuro en el utillaje. En este marco, se pretende obtener herramientas que permitan evaluar criterios de selección y diseño en los procesos relacionados con el desarrollo y aplicación de nuevos aceros de herramientas, con una óptima relación tenacidad-resistencia al desgaste. Si bien la mecánica de fractura permite establecer criterios de selección y diseño, no existen teorías fiables y universalmente aceptadas para la predicción del deterioro superficial de materiales (entre ellos el desgaste). En este sentido, la simulación por ordenador mediante el método de los elementos finitos de los fenómenos de fricción y desgaste se plantea como una interesante y escasamente reportada vía de aproximación al problema. El objetivo de este trabajo es ofrecer una primera aproximación a la compleja problemática asociada con la obtención de herramientas predictivas del fenómeno de desgaste empleando simulación numérica. Los resultados obtenidos se contrastan con ensayos experimentales de desgaste de Pin sobre disco en aceros de trabajo en frío DIN W-1.2379

  • Plastic behaviuor of green powder metallurgical compacts

     Prado Pozuelo, Jose Manuel; Riera Colom, Maria Dolores
    Materials science forum
    Vol. 534-536, num. 1, p. 305-308
    DOI: 10.4028/www.scientific.net/MSF.534-536.305
    Date of publication: 2007-01
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The results of monotonic and cyclic uniaxial compression tests, in which the deviatoric component of the stress is predominant, carried out on green and recrystallized iron compacts with different levels of density are presented and discussed in order to analyse the macro and micromechanisms governing the mechanical behaviour of non-sintered PM materials. The plastic deformation of the particles, especially at the contact areas between neighbouring particles, produces an internal friction responsible for the main features observed in the behaviour of green metallic compacts. These experimental results show important discrepancies with the plasticity models, Cam-Clay and Drucker-Prager Cap, used to simulate the powder compaction stage. Possible causes for these discrepancies are pointed out.

  • The elastic behaviour of metal powder compacts

     Prado Pozuelo, Jose Manuel; Riera Colom, Maria Dolores
    Materials science forum
    Vol. 534-536, num. 1, p. 325-328
    DOI: 10.4028/www.scientific.net/MSF.534-536.325
    Date of publication: 2007-01
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Access to the full text
    Simulación del funcionamiento nominal de un servofreno  Open access

     Brígido Belmonte, Albert; Cortés, Esteve; Riera Colom, Maria Dolores
    Reunión de Usuarios de ABAQUS
    p. 1-10
    Presentation's date: 2007-11-05
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    El servofreno es una parte del sistema de frenado de los vehículos que amplifica la fuerza realizada por el conductor sobre el pedal de freno. Éste mecanismo aprovecha la aportación de vació por parte del motor para, posteriormente, aportar presión al líquido de frenos y así poder disminuir la velocidad del vehículo. Con la finalidad de crear un nuevo diseño de servofreno, es necesario realizar una simulación para obtener el estado de tensiones y deformaciones de cada una de las piezas que lo componen. Mediante un cálculo en ABAQUS/Standard, sobre una etapa nominal de frenado, se observa cual es el comportamiento de cada uno de los elementos que intervienen en el mecanismo del servofreno

  • Access to the full text
    Tool steel selection for cold forming of high strength steels based on the stress distribution in tools  Open access

     Hernandez Rossi, Ricardo; Riera Colom, Maria Dolores; Casellas Padro, Daniel; Valls, Isaac; Prado Pozuelo, Jose Manuel; Casas Aguirregomezcorta, Begoña
    Materials Science & Technology Conference
    p. 235-243
    Presentation's date: 2007-09-16
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    The excellent combination of high mechanical strength, high elongation and strain hardening of Advanced High Strength Steels (AHSS) has allowed their increasing use in the automobile industry to reduce vehicle weight and thereby fuel consumption while improving crash performance. However, the implementation of such high strength materials has generated difficulties related to wear acceleration and premature failure of forming tools. High loading during cold forming of AHSS increases to a great extent the tool requirements in terms of toughness and hardness properties. The main alternative to overcome these difficulties involves an optimized selection tool material through a proper evaluation of the stress state in the tools themselves. In this work, stress states on tooling during cold forming of AHSS have been evaluated by means of finite element simulation. The calculated results allow selecting the most suitable tool steel in terms of microstructure and mechanical properties.

  • Simulación de fenómenos de desgaste mediante el uso de ABAQUS/SCRIPTING

     Hernandez Rossi, Ricardo; Riera Colom, Maria Dolores
    Reunión Nacional de Usuarios de SIMULIA
    p. 1-7
    Presentation's date: 2007-11-05
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Access to the full text
    Modelización y simulación de la etapa de compactación en pulvimetalurgia  Open access

     Riera Colom, Maria Dolores; Prado Pozuelo, Jose Manuel
    Revista de metalurgia
    Vol. 42, num. 6, p. 456-462
    Date of publication: 2006
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    La industria pulvimetalúrgica está interesada en extender las aplicaciones y mejorar la calidad de sus productos. Para ello, necesita un conocimiento detallado de sus procesos que permita su control. La representación del comportamiento mecánico de estos materiales se ha realizado utilizando diversos tipos de modelos; en la actualidad, la mayoría de los grupos de trabajo considera a los polvos metálicos como materiales granulares. Los modelos de plasticidad definidos para los materiales geológicos se están aplicando a los agregados metálicos. Sin embargo, ninguno de los modelos conocidos puede representar adecuadamente su comportamiento mecánico, especialmente en estados de fallo.

  • Modelización y simulación del comportamiento mecánico de materiales elastoméricos

     Riera Colom, Maria Dolores; Sanchez Soto, Miguel Angel; Gordillo Aubert, Antonio; Prado Pozuelo, Jose Manuel
    Congreso Nacional de Materiales
    p. 247-253
    Presentation's date: 2006
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Aplicación de materiales en el conformado de aceros de alta resistencia

     Casellas Padro, Daniel; Caro, Jaume; Beltran, Alfred; Riera Colom, Maria Dolores; Molas i Busquets, Sílvia; Hernandez Rossi, Ricardo; Prado Pozuelo, Jose Manuel
    Congreso Nacional de Materiales
    p. 835-838
    Presentation's date: 2006
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Estudio experimental del llenado de moldes pulvimetalúrgicos

     Isturiz, A; Riera Colom, Maria Dolores; Prado Pozuelo, Jose Manuel
    Revista de metalurgia
    Vol. Extraor., p. 181-186
    Date of publication: 2005-10
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Access to the full text
    Modelización y simulación del desgaste en aceros de herramientas  Open access

     Hernandez Rossi, Ricardo; Riera Colom, Maria Dolores; Prado Pozuelo, Jose Manuel
    Reunión Nacional de Usuarios de SIMULIA
    Presentation's date: 2005-11-11
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    El desgaste y fallo en útiles de mecanizado y conformado es un problema cada vez mas acuciante, debido a las exigencias cada vez mayores a las que se ven sometidos: mecanizar a mayor velocidad o conformar materiales mas resistentes. ABAQUS es una importante herramienta para estudiar estos fenómenos; así pues, en este trabajo se presenta una muestra de diversas estrategias para modelizar procesos de desgaste y a su vez dar una perspectiva de la implementación de los nuevos criterios de fallo incorporados por el programa en la última versión.

  • Access to the full text
    Experimental and numerical study of the die filling stage in powder metallurgy  Open access

     Cante Teran, Juan Carlos; Oliver Olivella, Fco. Javier; González Ferrari, Carlos; Riera Colom, Maria Dolores; Istúriz, Álvaro; Prado Pozuelo, Jose Manuel
    European Congress and Exhibition on Powder Metallurgy
    p. 339-344
    Presentation's date: 2005
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    The aim of this work is to show the potential of the Particle Finite Element Method (PFEM) in the simulation of the powder transfer stage, in powder metallurgy industrial processes. The most innovative aspects of the work are: a) the intensive use of the particle finite element method technology to trace the motion of a representative set of particles in the solid and b) the solution of inherent problems associated with new meshing definition and data transfer during the calculation. Comparison of experimental results and numerical simulations are used to assess the performance of the method

  • Determinación del estado tensional en útiles de conformado de aceros de alta resistencia y aplicación a aceros de herramientas

     Hernandez Rossi, Ricardo; Riera Colom, Maria Dolores; Casellas Padro, Daniel; Prado Pozuelo, Jose Manuel
    Congreso Nacional de Tratamientos Térmicos y de Superficie
    p. 233-240
    Presentation's date: 2005-10
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Access to the full text
    Data generation for the numerical simulation of powder compaction  Open access

     Prado Pozuelo, Jose Manuel; Riera Colom, Maria Dolores
    European Congress and Exhibition on Powder Metallurgy
    p. 301-306
    Presentation's date: 2005
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Numerical simulation of industrial plastic deformation processes needs of a precise characterization of the mechanical material properties included in the particular elastoplastic model. The plasticity model of bulk metallic materials is well known and the tests used for characterization are simple and well typified. The situation is quite different when the compaction of metal and ceramic powder has to be simulated; in this case, both, plasticity models and the corresponding mechanical tests are under discussion and research. Irrespective of the plastic model being employed more parameters and more complex than in the case of bulk materials must be determined. In this work the experience gained in this field by the joint effort of the research groups participating in the recently finished European Network Dienet is presented

  • Access to the full text
    Simulación de desgaste mediante la sub-rutina "umeshmotion"  Open access

     Hernandez Rossi, Ricardo; Riera Colom, Maria Dolores; Prado Pozuelo, Jose Manuel
    Reunión de Usuarios de ABAQUS
    p. 1-8
    Presentation's date: 2005-11-20
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    El primer paso para abordar el problema del desgaste en útiles de matriceria es conocer la distribución de tensiones en las herramientas y la magnitud de las presiones de contacto, a partir de dicha información es posible predecir el volumen desgastado de la herramienta. Un inconveniente importante en esta estrategia es que la evaluación de esfuerzos y presiones se realiza sobre la geometría original. El desgaste es un fenómeno en el cual la superficie de contacto se modifica progresivamente en el tiempo y por ende las tensiones en el sistema no son constantes. Mediante la subrutina UMESHMOTION es posible actualizar la geometría de la zona en contacto, de forma automática, en cada incremento de tiempo, utilizando como base un modelo de desgaste. Dicha subrutina se sustenta en un análisis de mallado adaptativo ALE sobre ABAQUS/Standad.

  • Recent advances on the numerical and experimental study of the powder transfer stage in powder metallurgy

     Cante Teran, Juan Carlos; Oliver Olivella, Fco. Javier; González Ferrari, Carlos; Riera Colom, Maria Dolores; Istúriz, Álvaro; Prado Pozuelo, Jose Manuel
    Powder Metallurgy Congress & Exhibition
    p. 345-350
    Presentation's date: 2005
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Access to the full text
    Experimental study of mass flow and apparent density in powder metallurgy die filling  Open access

     Riera Colom, Maria Dolores; Istúriz, Álvaro; Prado Pozuelo, Jose Manuel
    European Congress and Exhibition on Powder Metallurgy
    p. 175-182
    Presentation's date: 2005
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Die filling is the first step in the process of powder compaction. The density distribution after die filling on the powder properties and the method of filling. In this work the authors study the effects of powders characteristics, size and morphology, and shoe speed on the type of mass flow during the filling and the resulting density distribution. Experimental results for different powders and die geometries are presented. Three flow regimes have been identified and their influence on apparent density is discussed

  • Informe de evolución de la simulación. Etapa-2

     Sanchez Soto, Miguel Angel; Riera Colom, Maria Dolores
    Date: 2004-01
    Report

     Share Reference managers Reference managers Open in new window

  • Comportamiento elástico de piezas sinterizadas sometidas a estados compresivos de tensión

     Marbá, I; Riera Colom, Maria Dolores; Prado Pozuelo, Jose Manuel
    Congreso Nacional de Propiedades Mecánicas de Sólidos
    p. 68
    Presentation's date: 2004
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window