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 = Mecánica

Mostrando recursos 1 - 20 de 150

  1. Neural Network and Training Strategy Design for Train Drivers’ Vibration Dose Simulation

    Muñoz Guijosa, Juan Manuel; Riesco, Enrique; Olmedo, M.
    Vibration can cause professional illnesses in train drivers, giving also rise to lawsuits to the employer. A possible cause may be the lack of systematic vibration estimation processes, due to operational complexities, subjectivities involved and the cost of dedicated tests. Estimation quality may be improved by using a driver seat model along with cabin floor vibration data acquired during the train dynamic approval tests. However, due to the nonlinearities present, analytical models frequently show inaccurate results.

  2. Silla de ruedas de bajo coste, destinada a minusválidos, en países de escasos recursos económicos

    Molino Díaz, Jorge
    El objetivo de este Trabajo Fin de Grado es el desarrollo de una silla de ruedas de bajo coste, destinada a minusválidos, en países de escasos recursos económicos. Inicialmente, este trabajo incluye una introducción de carácter deductivo, puesto que va de lo general a lo particular. En ella se abordan los diferentes tipos de limitaciones en la actividad que pueden tener los seres humanos y que les sitúa en un estado de desventaja social. A continuación, se comentan las distintas ayudas técnicas que se han ido construyendo a lo largo del tiempo para disminuir esa diferencia y, en concreto, se...

  3. Design and Biomechanical Simulation of Custom Dental Implants

    Ojeda, Carlos; Céspedes, Javier; Chumán, Victor; Arriola, Alonso; Díaz Lantada, Andrés
    The design and simulation of some proposals of unconventional and conventional dental implants and their results are presented. The process of obtaining models with reverse engineering in Mimics, mechanical simulations in ANSYS and some results and tests with an algorithm of remodeling meant to simulate the behavior of the possible influence of stem cells in the proposed implants are explained.

  4. Modelling of the mechanical behaviour of the photopolymerization processes of resins intended for additive manufacturing (AMT) using laserstereolithography: The influence on part quality

    Blas Romero, Adrián de; Fernández, Guillermo; Díaz Lantada, Andrés
    This study presents a simplified model of the polymerization process of photo-cured epoxy resin, with the aim of finding theoretical values for the mechanical properties of the material in its transition stage from liquid to solid state, approximating these properties to a single figure at the instant of its gelation in the time denominated as tg. By evaluating a phenomenon observed during the fabrication of samples using a stereolithography additive manufacturing printer, it is hoped to fit a model that will replicate the mechanical forces undergone by the manufactured part. The introduction of new hypotheses to simplify the case under...

  5. Rheological characterization of lubricants using a tribometer

    Chacón Tanarro, Enrique; Echávarri Otero, Javier; Guerra Ochoa, Eduardo de la; Arribas Fernández, N.
    This work presents a methodology for predicting the Non-Newtonian behavior of monodisperse lubricants under typical pressure, temperature and shear rate conditions for elastohydrodynamic (EHD) contacts. For its correct application we require some tests using a conventional point contact tribometer and information on the low shear viscosity and density variations with pressure and temperature -these characteristics can be easily found in technical documents or by testing-. Finally, this procedure is validated testing a PAO-6 base oil.

  6. Design of a rib impactor equipment

    Torres, C. R.; García, G.; Aguilar, L. A.; Martínez Sáez, Luis
    The human ribs must be analyzed as long and as curved bones, due to their physiology. For the development of an experimental equipment that simulate the application of loads, over the rib in the moment of a frontal collision in an automobile with seat belt, it was applied a methodology that constituted in the identification of needs and the variables which led the design of 3D model, from this it was used the technique of fused deposition modeling for the development of the equipment pieces. The supports that hold the rib ends were design with two and three degrees of...

  7. THE ROLE OF SURFACE TEXTURING IN REDUCING FRICTION OF NON-CONFORMAL CONTACTS UNDER MIXED LUBRICATION

    Echávarri Otero, Javier; Guerra Ochoa, Eduardo de la; Chacón Tanarro, Enrique; Bellón Vallinot, Irene; Hernández, Javier
    This work analyses the effects of surface texturing on friction under different lubrication regimes by means of experiments performed with non-conformal contacts. Different texturing designs were created on the surfaces of testing specimens by means of a photolithography and chemical etching process. The testing conditions were selected using a theoretical model for predicting film thickness, which ensure that experimental conditions cover from fluid film to mixed lubrication. The results show that some designs of textured surfaces achieve important reductions in friction, especially under mixed lubrication conditions.

  8. Rheological Characterization of Lubrocants Using a Tribometer

    Chacón Tanarro, Enrique; Echávarri Otero, Javier; Guerra Ochoa, Eduardo de la
    This work presents a methodology for predicting the Non-Newtonian behavior of monodisperse lubricants under typical pressure, temperature and shear rate conditions for elastohydrodynamic (EHD) contacts. For its correct application we require some tests using a conventional point contact tribometer and information on the low shear viscosity and density variations with pressure and temperature -these characteristics can be easily found in technical documents or by testing-. Finally, this procedure is validated testing a PAO-6 base oil.

  9. A Fluid-Dynamic Numerical Model for the Selective Laser Melting of High-Thickness Metallic Layers

    Cordovilla Baró, Francisco; Garzón, Miguel; Muñoz, Diego Alejandro; Díaz, Javier; García Beltrán, Ángel; Ocaña Moreno, José Luis
    Productivity in the Selective Laser Melting Process (SLM) is directly related with the thickness of the powder bed that is repeatedly applied, at every increment, in the growing of consolidated material in the additive manufacturing process. Although most of the relevant phenomena (limited diffusivity associated to particles contact, phase changes, gradients of surface tension associated with Marangoni convection, or even recoil pressure) are considered in the models with small bed thicknesses (roughly 20 µm ? 40 µm), in the case of larger thicknesses (between 100 µm and 200 µm) these factors strongly influence the size and shape of the fusion...

  10. Analysis Of The Effect Of Surface Oxidation On The Laser Transformation Hardening Of Cr-mo Steels

    Cordovilla Baró, Francisco; García Beltrán, Ángel; Domíngez, Jesús; Sancho, Paula; Ocaña Moreno, José Luis
    Laser surface hardening is a technology that enables important advantages to be obtained in comparison with conventional techniques in terms of accuracy of the heat affected zone and productivity. Nevertheless, the development of realistic and flexible models has to be fulfilled in order to control the effects of every set of process conditions. Despite many different models having been developed, very few of them deal with the increment of absorption related with the instantaneous value of the layer of oxide growth during the process in a non-protective atmosphere. This work analyzes, on one hand, the problem of oxide formation at...

  11. Fragilización por hidrógeno: estudio de la influencia de la energía de las trampas mediante simulación de Monte Carlo

    Alonso, J.; Ridruejo Rodríguez, Álvaro; Sánchez, J.
    La fragilización por hidrógeno es una de las principales causas de fallo de los metales que se encuentran bajo solicitaciones mecánicas estáticas. Para el caso de los aceros, existen numerosos estudios y diversos mecanismos que tratan explicar todos los fenómenos de Fragilización por Hidrógeno. En el caso del transporte de Hidrógeno por la red de hierro se han tenido en cuenta las trampas para poder calcular un coeficiente de difusión efectivo. En este trabajo se propone un estudio sobre la cinética de atrapamiento del hidrógeno considerando una trampa de baja energía, equivalente a una vacante. En este estudio, los cálculos...

  12. Diseño conceptual y preliminar de una motocicleta deportiva con sistema de suspensión de doble basculante (dual-link)

    Del Buono González, Antonio Benito
    Este proyecto ha sido realizado con el objetivo de diseñar un prototipo de motocicleta deportiva con suspensión delantera alternativa, que pueda rivalizar con los modelos actuales con horquilla telescópica, ofreciendo un mejor comportamiento dinámico y manteniéndose dentro de un rango de precio competitivo. El proyecto incluirá no solo la realización del chasis y el mecanismo, sino que buscará presentar un producto completo que incluya todos los componentes mecánicos de una motocicleta, así como el carenado, faros y resto de elementos. El sistema de suspensión elegido hará uso de un mecanismo que resulta de la combinación de un sistema de buje central...

  13. Linear approximation of the behavior of the rotator cuff under fatigue conditions. Violinist case study

    Islán Marcos, Manuel Enrique; Carvajal Ahumada, Jorge; San Pedro, Pilar; D'Amato, Roberto; Juanes Méndez, Juan Antonio; Soriano Heras, Enrique
    The repetitive or sustained movements, that are now intrinsic in work routines, are often direct cause of musculoskeletal injuries located in the shoulder. In the case of the violinists it should be added that these movements are forced, which represents an aggravating to the situation. The present work aims to study the behavior of the glenohumeral joint under different postures that represent the routine of a violinist and under RULA criteria (rapid upper limb assessment). A FEM analysis of the joint was developed by using ANSYS® [VERSION 17.1] software and as geometry of the joint a model generated in CATIA®...

  14. Perpendicular ultrasonic joining of steel to aluminium alloy plates

    Muñoz Guijosa, Juan Manuel; Nanaumi, Genki; Ohtani, Kazuki
    Standard and high strength steel plates were successfully joined to A2017 and A6061 aluminium plates by applying ultrasonic power perpendicular to the joint interface instead of tangentially, as in other ultrasonic joining methods Using a 2.9 mm diameter tip, cross tensile strengths of 281 N and 460 N were obtained when joining 0.5 mm thick A6061 plates to 0.5 mm thick commercial and high steel plates, respectively. When joining 0.5 mm thick A2017 plates, the cross tensile strengths were 343 N and 437 N, respectively. Temperature measured at less than 1?mm from the joining interface did not exceed 135 °C...

  15. Grimme consolida su apuesta por las cosechadoras de remolacha

    Moya Gonzalez, Adolfo
    La granja Grimme, ubicada en la localidad de Cappeln, en la Baja Sajonia, fue el lugar elegido por la marca para presentar junto con Amazone sus principales novedades para la próxima edición de la feria de Hanover. La presentación del evento fue llevada a cabo por Franz Grimme, director del grupo.

  16. Free form metallization of solar cells using Laser Induced Forward Transfer

    Muñoz Martín, David; Chen, Yu; Canteli Pérez Caballero, David; Morales Furió, Miguel; Molpeceres Álvarez, Carlos Luis
    Front metallization is an expensive, fundamental step in the fabrication of solar cells. Laser additive direct writing techniques, such as Laser Induced Forward Transfer (LIFT), can be used for printing optimized metallization patterns or free form personalized designs with applications in building integrated photovoltaics. In this work, metallic fingers and busbars have been printed onto different rigid and flexible photovoltaic materials using commercial, high viscosity, micron-sized particles, silver-based pastes. Printed lines show very large aspect ratios, low electrical resistivity and good adherence to the substrate. Functional test cells have been metallized from unfinished CIGS flexible solar cells.

  17. Laser functionalization of surfaces

    Canteli Pérez Caballero, David; Márquez Fernández, Andrés; Muñoz Martín, David; Faleiro Rodríguez, Gabriel; Santamaría Riocerezo, Samuel; Lauzurica Santiago, Sara; Morales Furió, Miguel; Molpeceres Álvarez, Carlos Luis
    The treatment of surfaces by physical or chemical methods is a very usual way to change their original properties. Although the most common use of a surface functionalization is for tribology aims, modifications of the topography that leads to changes in the surface roughness, its hydrophilicity or hydrophobicity, its light scattering behavior, biocompatibility or even aesthetic changes are possible. In this field, laser sources have proven to be a most versatile and useful tool, being a clean and fast way to achieve any of those objectives. In this work we show the results of functionalization by laser texturing of four...

  18. Laser Direct Writing techniques for metallization of solar cells

    Muñoz Martín, David; Chen, Yu; Morales Furió, Miguel; Canteli Pérez Caballero, David; Molpeceres Álvarez, Carlos Luis
    Front metallization is an expensive, fundamental step in the fabrication of solar cells. It comprises different processes including the printing of fingers and busbars and several thermal treatments in order to cure and sinter the printed material. These two steps have been replaced by laser direct writing techniques, what allows printing fully personalized metallization designs, with high throughput velocities and a lower thermal budget for the solar cell structure.

  19. A Simple Energy-conserving Torsion-free Beam Element for Multibody Applications

    García Orden, Juan Carlos
    Slender flexible beams are very common in many applications in different fields related to multibody dynamics: robotics, aerospace mechanisms, computer graphics, etc. Typically, these components experience small strains but large displacements and rotations. What is more, ofter their torsional strains are very small or null, due to their slenderness or the specific type of kinematical pairs that connect them with other parts of the mechanism. The numerical simulation of the dynamical behavior of such systems demand the development of beam elements capable of representing these nonlinear effects, while providing accurate results when used with a time-marching scheme. Many different approaches...

  20. Interdigitated laser-contacted solar cell on liquid-phase crystallized silicon on glass

    Vetter, Michael; López Rodríguez, Gema; Ortega, Pablo; Martín, Isidro; Andrä, Gudrun; Muñoz Martín, David; Molpeceres Álvarez, Carlos Luis
    10 µm thick liquid-phase crystallized silicon (Si) layers on 3.2 mm Borofloat 33 glass (5cm x 5cm) are fabricated by continuous wave line focus laser (808 nm). A sputtered SiO2/SiON layer stack has been implemented as barrier layer at the glass Si interface. Solar cells with interdigitated back contact are prepared on these multicrystalline layers by using low temperature (<400ºC) Doped-by-Laser (DopLa) fabrication concept. ALDAl2O3/ PECVD amorphous intrinsic Si carbide (SiCx(i)) stack for emitter passivation and a-SiCy(i)/P-doped a- SiCz(n)/a-SiCx(i) stack for base passivation are deposited. With short pulse (ns) UV laser (355 nm) p-type emitter (by Al-diffusion from Al2O3) and...

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