Persona: Fernández Bermejo, Daniel
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Publicación Predictive Analytics-Based Methodology Supported by Wireless Monitoring for the Prognosis of Roller-Bearing Failure(MDPI, 2024-06-17) Primera, Ernesto; Cacereño, Andrés; Fernández Bermejo, Daniel; Rodríguez Prieto, ÁlvaroRoller mills are commonly used in the production of mining derivatives, since one of their purposes is to reduce raw materials to very small sizes and to combine them. This research evaluates the mechanical condition of a mill containing four rollers, focusing on the largest cylindrical roller bearings as the main component that causes equipment failure. The objective of this work is to make a prognosis of when the overall vibrations would reach the maximum level allowed (2.5 IPS pk), thus enabling planned replacements, and achieving the maximum possible useful life in operation, without incurring unscheduled corrective maintenance and unexpected plant shutdown. Wireless sensors were used to capture vibration data and the ARIMA (Auto-Regressive Integrated Moving Average) and Holt–Winters methods were applied to forecast vibration behavior in the short term. Finally, the results demonstrate that the Holt–Winters model outperforms the ARIMA model in precision, allowing a 3-month prognosis without exceeding the established vibration limit.Publicación Effect of Process Parameters and Definition of Favorable Conditions in Multi-Material Extrusion of Bimetallic AZ31B–Ti6Al4V Billets(MDPI) Fernández Bermejo, Daniel; Rodríguez Prieto, Álvaro; Camacho López, Ana MaríaThis paper investigates the extrusion process to manufacture bimetallic cylinders combining a magnesium alloy core (AZ31B) and a titanium alloy sleeve (Ti6Al4V) of interest in aeronautical applications. A robust finite element model has been developed to determine the most influential parameters and to study the effect of them on the extrusion force and damage induced by means of Design of Experiments (DOE) and Taguchi method. The results show that the most influential parameters in the extrusion forces are the friction between sleeve and container/die and the height of the cylinder; and the less influential ones are the process temperature and ram speed. Moreover, minimum values of forces along with low damage can be reached by favorable interface contact conditions, minimizing the friction at the core-container/die interface, as the main influencing factor; followed by the geometrical dimensions of the billet, being the billet height more important when paying attention to the minimum forces, and being the core diameter when considering the minimum damage as the most important criterion. The results can potentially be used to improve the efficiency of this kind of extrusion process and the quality of the extruded part that, along with the use of lightweight materials, can contribute to sustainable production approaches.Publicación Data analytics-driven selection of die material in multimaterial co-extrusion of Ti-Mg alloys(MDPI, 2024-03-10) Fernández Bermejo, Daniel; Rodríguez Prieto, Álvaro; Camacho López, Ana MaríaAbstract: Selection of the most suitable material is one of the key decisions to be taken at the design stage of a manufacturing process. Traditional approaches as Ashby maps based on material properties are widely used in the industry. However, in the production of multimaterial components, the criteria for the selection can include antagonistic approaches. The aim of this work is the implementation of a methodology based on the results of process simulations for several materials and classify them by applying an advanced data analytics method based on Machine Learning (ML), in this case the Support Vector Regression (SVR) and Multi-Criteria Decision Making (MCDM) meth- odologies, specifically Multi-criteria Optimization and Compromise Solution (VIKOR) combined with Entropy weighting methods. In order to do this, a Finite Element Model (FEM) has been built to evaluate the extrusion force and the die wear in a multi-material co-extrusion process of bimetallic Ti6Al4V-AZ31B billets. After applying SVR and VIKOR combined with Entropy weighting methodologies, a comparison has been established based on the material selection and complexity of the methodology used, resulting that material chosen in both methodologies is very similar and MCDM method is easier to implement because there is no need of evaluate the error of the prediction model and the time for data preprocessing is less than the time needed in SVR. This new methodology is proven to be effective as alternative to the traditional approaches and aligned with the new trends in the industry based on simulation and data analytics.Publicación Optimal Parameters Selection in Advanced Multi-Metallic Co-Extrusion Based on Independent MCDM Analytical Approaches and Numerical Simulation(MDPI, 2022-11-28) Fernández Bermejo, Daniel; Rodríguez Prieto, Álvaro; Camacho López, Ana MaríaMulti-material co-extrusion is a complex thermo-mechanical forming process used to obtain bimetallic billets. Its complexity is due to the combination of diffusion phenomena in the interface of both materials together with the high temperature and pressure generated and the different flow stress characteristics created by the joining of dissimilar materials. Accordingly, the selection of optimal process parameters becomes key to ensure process feasibility. In this work, a comparison among different multi-criteria decision making (MCDM) methodologies, together with different eighting methods, were applied to the simulation results by using DEFORM3D© software to select the optimal combination of process parameters to fulfil the criteria of minimum damage, extrusion force, and tool wear, together with the maximum reduction in the average grain size.Publicación Analysis of AZ31B -Ti6Al4V bimetallic extrusion by numerical simulation and Taguchi method(Cambridge University Press, 2021-06-23) Fernández Bermejo, Daniel; Rodríguez Prieto, Álvaro; Camacho López, Ana MaríaThis paper investigates the extrusion force and damage induced during an extrusion process to manufacture bimetallic cylinders combining a titanium alloy sleeve (Ti6Al4V) and a magnesium alloy core (AZ31B). A study has been carried out to determine the damage factor distribution through the extrusion process and how this factor together with the extrusion force are influenced by the manufacturing parameters (extrusion ratio, friction and die semi-angle) by means of finite element (FE) simulations. Also, a Taguchi Design of Experiments (DoE) and an Analysis of Variance (ANOVA) have been performed in order to study the influence of each parameter to minimize the extrusion force needed to perform the process and the damage in the extrudate. The results show that damage distribution in the sleeve does not follow any pattern, appearing in different region in a random way. However, in the core the damage always occurs in the region outside the contour of the sleeve, where it reaches the maximum value and afterwards remains stationary during the rest of the process. In the core, damage increases as friction factor does and it is independent of the cross-section reduction for low die semi-angles (15°) and reaches the maximum values for 60° die semi-angle. In both cases, damage and extrusion force, the more relevant factor to obtain minimum values is the die semi-angle.Publicación Selection of die material and its impact on the multi-material extrusion of bimetallic AZ31B–Ti6Al4V components for aeronautical applications(MDPI, 2021-12-09) Fernández Bermejo, Daniel; Rodríguez Prieto, Álvaro; Camacho López, Ana MaríaThis paper investigates the effect that the selection of the die material generates on the extrusion process of bimetallic cylindrical billets combining a magnesium alloy core (AZ31B) and a titanium alloy sleeve (Ti6Al4V) of interest in aeronautical applications. A robust finite element model is developed to analyze the variation in the extrusion force, damage distribution, and wear using different die materials. The results show that die material is a key factor to be taken into account in multi-material extrusion processes. The die material selection can cause variations in the extrusion force from 8% up to 15%, changing the effect of the extrusion parameters, for example, optimum die semi-angle. Damage distribution in the extrudate is also affected by die material, mainly in the core. Lastly, die wear is the most affected parameter due to the different hardness of the materials, as well as due to the variations in the normal pressure and sliding velocity, finding critical values in the friction coefficient for which the die cannot be used for more than one forming stage because of the heavy wear suffered. These results can potentially be used to improve the efficiency of this kind of extrusion process and the quality of the extruded part that, along with the use of lightweight materials, can contribute to sustainable production approaches.Publicación Sobre el bien o bienes jurídicos protegidos de los artículos 379.2 (inciso primero) y 383 del Código penal. su relación concursal(Iustel, 2016) Fernández Bermejo, DanielEl presente trabajo trata de escudriñar el bien o bienes jurídicos protegidos en los delitos de los artículos 379.2, inciso primero, y 383 del Código Penal, paralelos y divergentes en el ámbito de la Seguridad Vial, a tenor de la amplia controversia generada doctrinal y jurisprudencialmente, realizando un recorrido normativo desde sus orígenes, hasta los comentarios más recientes. Así mismo, se relacionarán ambos tipos penales por la conexión que presentan entre sí en su exteriorización práctica, manifestando los distintos criterios de aplicación de las normas ante la ponderación concursal de estos delitos.Publicación El delito de conducción de vehículos de motor bajo la influencia de los efectos del alcohol(La Ley, 2016-03) Fernández Bermejo, DanielEl presente trabajo trata de analizar los elementos del delito de conducción bajo la influencia de bebidas alcohólicas desde un punto de vista práctico, dentro de la esfera del derecho penal, a través de la interpretación doctrinal y jurisprudencial. Esta modalidad delictiva aparece tipificada en el inciso primero del artículo 379.2 del Código Penal, adelantando la barrera protectora que el derecho penal ostenta como última ratio en el ordenamiento jurídico, en detrimento de la esfera administrativa que, tradicionalmente, se ha encargado de sancionar algunas infracciones que por determinadas razones de índole política, se han ido diluyendo con el transcurso del tiempo.Publicación El sistema de ejecución de condenas en España: el sistema de individualización científica Daniel Fernández Bermejo(Universidad de Santiago de Compostela, 2015) Fernández Bermejo, DanielEl presente trabajo trata de abordar el análisis normativo y práctico del actual sistema penitenciario español de individualización científica, el cual, en puridad, atiende a la evolución de la personalidad de los condenados a penas privativas de libertad, en armonía con la aplicación del tratamiento penitenciario individualizado. Asimismo, se prestará atención a los límites y carencias que presenta este sistema, y al esperanzador principio de flexibilidad penitenciario, que nutre y fortalece al sistema de individualización científica.Publicación En contra de la «cadena perpetua» en España (una vez más)a propósito del populismo político actual(La Ley, 2018) Fernández Bermejo, DanielEn el presente trabajo se pretende analizar la pena de prisión permanente revisable y su “desencaje” en el ordenamiento jurídico español, al contravenir algunos principios básicos imperantes en ámbito de la ejecución penal. Además, se pretende mostrar el genuino populismo existente en la clase política española al manifestar recientemente su interés por ampliar el catálogo de delitos que deberían llevar pareja esta pena incierta e indeterminada que estudiamos, tratando de empatizar de esta manera con las familias de las víctimas de los trágicos sucesos que están teniendo lugar, convirtiendo el Derecho penal en una herramienta básica electoral.