Investigaciones financiadas por la Unión Europea (OpenAire) - Europar Batasunak finantzatutako ikerketak (OpenAire)
Permanent URI for this collection
Browse
Browsing Investigaciones financiadas por la Unión Europea (OpenAire) - Europar Batasunak finantzatutako ikerketak (OpenAire) by Department/Institute "Ingeniaritza"
Now showing 1 - 19 of 19
Results Per Page
Sort Options
Publication Open Access Application-oriented data analytics in large-scale metal sheet bending(MDPI, 2023) Penalva Oscoz, Mariluz; Martín, Ander; Martínez, Víctor; Veiga Suárez, Fernando; Gil del Val, Alain; Ballesteros Egüés, Tomás; Favieres Ruiz, Cristina; Ingeniería; IngeniaritzaThe sheet-metal-forming process is crucial in manufacturing various products, including pipes, cans, and containers. Despite its significance, controlling this complex process is challenging and may lead to defects and inefficiencies. This study introduces a novel approach to monitor the sheet-metal-forming process, specifically focusing on the rolling of cans in the oil-and-gas sector. The methodology employed in this work involves the application of temporal-signal-processing and artificial-intelligence (AI) techniques for monitoring and optimizing the manufacturing process. Temporal-signal-processing techniques, such as Markov transition fields (MTFs), are utilized to transform time series data into images, enabling the identification of patterns and anomalies. synamic time warping (DTW) aligns time series data, accommodating variations in speed or timing across different rolling processes. K-medoids clustering identifies representative points, characterizing distinct phases of the rolling process. The results not only demonstrate the effectiveness of this framework in monitoring the rolling process but also lay the foundation for the practical application of these methodologies. This allows operators to work with a simpler characterization source, facilitating a more straightforward interpretation of the manufacturing process.Publication Open Access Chemical and mechanical stability of air annealed cathodic arc evaporated CrAlON coatings(Elsevier, 2018) Almandoz Sánchez, Eluxka; García Fuentes, Gonzalo; Martínez de Bujanda Carasusán, Javier; Rodríguez Trías, Rafael; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; IngenieríaThis study reports the synthesis and characterization of ternary Cr-Al-O and quaternary Cr-Al-O-N coatings deposited by cathodic arc physical vapour deposition, for various nitrogen and oxygen mass flow ratios during the growth process. The composition, microstructure, indentation hardness and modulus of the films have been characterized by scanning electron microscopy, electron probe micro-analysis, X-ray diffraction, and nanoindentation techniques. The evolution of the microstructure and mechanical properties of the coatings after ambient air annealing from 800 °C up to 1100 °C have been investigated. As the oxygen to nitrogen mass flow increases, the as-deposited coatings exhibit lower hardness, higher roughness, lower crystallinity and a more marked columnar structure. At oxygen to nitrogen mass flow ratios bigger than 10/90, the coatings exhibit a stoichiometry of the type (CrAl)2+εO3−ε. Only the coatings with an oxygen to nitrogen mass flow ratio smaller than 10/90 retained nitrogen in their compositions. In all cases, the coatings developed a cubic fcc lattice structure. After annealing at 1100 °C the resulting microstructure showed a clear dependency upon the initial composition of the films. The evolution of the microstructure during the high temperature tests, as well as the analysis of the nanoindentation hardness, composition and thickness also provided valuable information about the combined effects of the thermal stability and the oxidation of the deposited coatings.Publication Open Access Comparative study of the metallurgical quality of primary and secondary AlSI10MnMg aluminium alloys(MDPI, 2021) Bakedano, Asier; Niklas, Andrea; Fernández‐Calvo, Ana Isabel; Plata, Gorka; Lozares, Jokin; Berlanga Labari, Carlos; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; IngenieríaThe use of secondary aluminium is increasingly being promoted in the automotive industry for environmental reasons. The purpose of this study was to demonstrate that it is possible to obtain a recycled AlSi10MnMg(Fe) aluminium alloy with equal metallurgical quality to that of a primary AlSi10MnMg alloy when an adequate melt treatment is applied. The melt treatment consisted of deoxidation, degassing and skimming in accordance with the detailed procedure described in this article. The metallurgical qualities of one primary and two secondary alloys were assessed using thermal analysis, the density index test, the macroinclusion test and the microinclusion level test before and after melt treatment. The thermal analysis allowed us to compare the variables of the solidification cooling curve (Al primary temperature and its undercooling; Al‐Si eutectic temperature and its predictive modification rate). The density index test was used to evaluate the hydrogen gas content in the melt. The macroinclusion test was used to evaluate the melt cleanliness, while the microinclusion level test was used to perform the inclusion identification and quantification analyses. This study showed the feasibility of manufacturing structural components using 100% recycled secondary aluminium alloy through V‐ HPDC technology.Publication Open Access A comparison of performance of SWAT and machine learning models for predicting sediment load in a forested Basin, Northern Spain(Elsevier, 2021) Jimeno-Sáez, Patricia; Martínez-España, Raquel; Casalí Sarasíbar, Javier; Pérez-Sánchez, Julio; Senent-Aparicio, Javier; Ingeniería; Ingeniaritza; Gobierno de Navarra / Nafarroako GobernuaIn water bodies, sediment transport is a potential source of numerous negative effects on water resource projects and can damage environmental services. Two machine learning (ML) algorithms, the M5P and random forest (RF) models, have been explored for the first time as alternatives to the Soil and Water Assessment Tool (SWAT) model to estimate suspended sediment load (SSL) in the Oskotz river basin, a forested experimental basin in Navarra, northern Spain. In the ML models, streamflow and precipitation data were used to estimate daily SSL, testing different combinations of these inputs. The ML models were more accurate than the physically based hydrological SWAT model for all input scenarios tested at the daily scale. Moreover, although the SWAT results improved considerably at the monthly scale, the statistics obtained were generally inferior compared to the ML models. For the best combination of inputs, M5P demonstrated a superior ability to estimate SSL (R2 = 0.73, MAE = 135.04, RSR = 0.54, NSE = 0.71 and PBIAS = 5.19), compared to RF (R2 = 0.72, MAE = 143.39, RSR = 0.57, NSE = 0.67 and PBIAS = 11.60) and SWAT (R2 = 0.57, MAE = 181.24, RSR = 0.65, NSE = 0.57 and PBIAS = -1.27). The average sediment loads in winter, the season with the highest sediment generation in the Oskotz basin, were 2,094.04, 1,831.08 and 2,242.67 tonnes for M5P, RF and SWAT, respectively, compared to an observed SSL of 1,878.16 tonnes. These results indicate that M5P and RF are suitable models for simulating fluvial sediment production since they improved the results of the SWAT model, which also requires more time and data to set up and calibrate. However, since SWAT does not require observed streamflow as an input, it remains a useful model, achieving acceptable results in basins with limited streamflow data.Publication Open Access Complex selective manipulations of thermomagnetic programmable matter(Springer Nature, 2022) Irisarri Erviti, Josu; Ezcurdia Aguirre, Íñigo Fermín; Sandúa Fernández, Xabier; Galarreta Rodríguez, Itziar; Pérez de Landazábal Berganzo, José Ignacio; Marzo Pérez, Asier; Ciencias; Zientziak; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Institute of Smart Cities - ISCProgrammable matter can change its shape, stiffness or other physical properties upon command. Previous work has shown contactless optically controlled matter or magnetic actuation, but the former is limited in strength and the latter in spatial resolution. Here, we show an unprecedented level of control combining light patterns and magnetic fields. A mixture of thermoplastic and ferromagnetic powder is heated up at specific locations that become malleable and are attracted by magnetic fields. These heated areas solidify on cool down, and the process can be repeated. We show complex control of 3D slabs, 2D sheets, and 1D filaments with applications in tactile displays and object manipulation. Due to the low transition temperature and the possibility of using microwave heating, the compound can be manipulated in air, water, or inside biological tissue having the potential to revolutionize biomedical devices, robotics or display technologies.Publication Embargo Development of sustainable stabilized rammed earth building materials based on by-products(2025) Martín Antunes, Miguel Ángel; Bascoules Perlot, Céline; Seco Meneses, Andrés; Ingeniería; Ingeniaritza; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaEn esta tesis doctoral, se desarrolló un material basado en subproductos locales para su uso como material de construcción de Tapial Estabilizado (SRE) en el sector de la construcción. Los materiales considerados como subproductos son producidos localmente dentro de la Eurorregión, específicamente en Navarra. El material desarrollado en la tesis doctoral constituye una aplicación para estos subproductos, que carecen de formas efectivas de valorización, evitando su disposición en vertederos, reduciendo los costos de gestión y ahorrando recursos naturales. Además, ayudaría al sector de la construcción de la Eurorregión a mitigar su huella ambiental. La ejecución del proceso de investigación requerido para el desarrollo de esta tesis doctoral se llevó a cabo utilizando una metodología dividida en cuatro fases. En la primera fase, se realizó una revisión bibliográfica exhaustiva sobre SRE. A través del análisis de la información recopilada, se propuso una metodología para la fabricación, curado y caracterización del material de construcción SRE. Esta metodología se aplicó en las siguientes fases de investigación que constituyen esta tesis doctoral. En la segunda fase, se identificaron y caracterizaron los subproductos locales con potencial para su uso en la construcción de SRE, con el fin de desarrollar una mezcla de subproductos naturales que pudiera reemplazar el suelo en la construcción de SRE. Se consideraron cuatro subproductos (tres diferentes subproductos mineros con diferente granulometría y un subproducto industrial, arena) como componentes de esta mezcla. Se llevó a cabo una campaña experimental para establecer las proporciones adecuadas para combinarlos en una mezcla optimizada adecuada para su uso en la construcción de tierra compactada mediante el modelo de diseño experimental Taguchi. Este método estadístico se aplicó para estudiar el efecto de diferentes distribuciones de tamaño de partículas (PSDs) en la construcción de tierra compactada, con el objetivo de maximizar la densidad en seco del material y la resistencia a compresión no confinada (UCS). En la tercera fase se decidió estabilizar la combinación en la que la PSD optimizó la densidad en seco con tres estabilizadores convencionales diferentes: cemento, cal hidratada calcárea y cal hidráulica natural. En la cuarta fase, con el fin de reducir el impacto ambiental de los estabilizadores convencionales, se estabilizó el material con PSD optimizada utilizando dos estabilizadores no convencionales diferentes. Se caracterizaron sus propiedades mecánicas y de durabilidad, siguiendo la metodología de la primera fase, y se compararon con las propiedades de SRE obtenidas con estabilizadores convencionales. Los estabilizadores no convencionales estudiados fueron un estabilizador basado en Mg (GGBS-PC8) y un cemento supersulfatado (SSC). Se realizaron dos campañas experimentales diferentes, donde se fabricaron seis combinaciones que fueron sometidas a pruebas de UCS, UCS sumergido, pruebas de durabilidad por humedecimiento y secado, SEM/EDS, TG/DTG y XRD. Las combinaciones estabilizadas con los estabilizadores no convencionales lograron mejores resultados que aquellas estabilizadas con los convencionales. Estos resultados demostraron el potencial de los estabilizadores no convencionales, los cuales, en el caso del GGBS-PC8, permitieron el desarrollo de un material de construcción 100% basado en materiales reciclados con propiedades técnicas y ambientales mejoradas.Publication Open Access Effects of climate change on streamflow and nitrate pollution in an agricultural mediterranean watershed in northern Spain(Elsevier, 2023) Oduor, Brian Omondi; Campo-Bescós, Miguel; Lana Renault, Noemí; Casalí Sarasíbar, Javier; Ingeniería; Ingeniaritza; Institute on Innovation and Sustainable Development in Food Chain - ISFOODPredicting water quality and quantity response to climate change in a watershed is very difficult due to the complexity and uncertainties in estimating and understanding future hydrological conditions. However, hydrological models could simplify the processes and predict future impacts of agricultural activities. This study aimed to evaluate the applicability of the Soil Water Assessment Tool (SWAT) model for climate change prediction of streamflow and nitrate load in an agricultural Mediterranean watershed in northern Spain. The model was first evaluated for simulating streamflow and nitrate load under rainfed agricultural conditions in the Cidacos River watershed in Navarre, Spain. Then, climate change impact analysis on streamflow and nitrate load was conducted in the short-term (2011–2040), medium-term (2041–2070), and long-term (2071–2100) future projections relative to the historical baseline period (1971–2000) under the RCP4.5 and RCP8.5 CO2 emission scenarios. The model evaluation showed a good model performance result during calibration (2000–2010) and validation (2011–2020) for streamflow (NSE = 0.82/0.83) and nitrate load (NSE = 0.71/0.68), indicating its suitability for adoption in the watershed. The climate change projection results showed a steady decline in streamflow and nitrate load for RCP4.5 and RCP8.5 in all projections, with the long-term projection scenario of RCP8.5 greatly affected. Autumn and winter saw a considerable drop in comparison to spring and summer. The decline in streamflow was attributed to the projected decrease in precipitation and increase in temperatures, while the nitrate load decline was consistent with the projected streamflow decline. Based on these projections, the long-term projection scenarios of RCP8.5 indicate dire situations requiring urgent policy changes and management interventions to minimize and mitigate the resulting climate change effects. Therefore, adapted agricultural management practices are needed to ensure sustainable water resource utilization and efficient nitrogen fertilizer application rates in the watershed to reduce pollution.Publication Open Access Evaluating the cradle-to-gate environmental impact and cooling performance of advanced daytime radiative cooling materials to establish a comparative framework for a novel photonic meta-concrete(Springer, 2024-10-08) Adams, Nick; Carlosena Remírez, Laura; Allacker, K.; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISCBackground By the end of 2050, it is expected that 68% of the population will live in urban areas. A higher density of people living in cities generates an increased urban heat island. Radiative cooling (RC) materials are proposed as a key strategy to mitigate global warming and urban heating. The Horizon 2020 project MIRACLE aims at developing a new RC material based on conventional concrete. This paper presents a framework developed for comparing both the cradle-to-gate environmental impact and cooling potential of the newly developed photonic meta-concrete (or any other new RC material) with existing RC materials. The framework is applied to various RC materials using the generic Ecoinvent v3.6 database. The impact assessment method is in line with the Belgian life cycle assessment method for buildings and covers the 15 environmental impact categories of the EN15804:A2. The cooling performance is assessed by implementing the material spectral emissivity into a thermal model for Brussels and Madrid. Results The study shows that the sputtering process contributes over 75% to the cradle-to-gate environmental impact of several RC materials, while materials produced without this process, have significantly lower impacts. The assessment of the cooling potential showed that convection heat gains make it difficult to create an all-year round cooling material. The comparison with a conventional building material, a concrete roof tile, hence shows great potential for these RC materials as heating gains during summer are significantly reduced. Analysing cooling performance alongside environmental impact, the study identified two RC materials, i.e. D6 and D10, as the most preferred in both Brussels and Madrid, considering their lower environmental impact and superior performance. Conclusions The literature review revealed that a standardised way to assess and benchmark RC materials based on their cradle-to-gate environmental impact and cooling performance is lacking to date. This paper hence presents, for the first time, a method to compare RC materials considering these two characteristics. This method allows to identify the most competitive RC materials, which will serve in our study to benchmark the newly developed photonic meta-concrete.Publication Open Access Evaluation of the impact of changing from rainfed to irrigated agriculture in a mediterranean watershed in Spain(MDPI, 2023) Oduor, Brian Omondi; Campo-Bescós, Miguel; Lana Renault, Noemí; Alfaro Echarri, Alberto; Casalí Sarasíbar, Javier; Ingeniería; Ingeniaritza; Institute on Innovation and Sustainable Development in Food Chain - ISFOODThe conversion of cultivated areas from rainfed to irrigated agriculture alters the watershed’s hydrology and could affect the water quality and quantity. This study examined how streamflow, nitrate load, and nitrate concentration changed after irrigation implementation in a Mediterranean watershed in Navarre, Spain. The Soil Water Assessment Tool (SWAT) model was applied in the Cidacos River watershed to simulate streamflow and nitrate load under rainfed conditions. The simulated outputs were then compared with the post-irrigation observed values from mid-2017 to 2020 at the watershed outlet in Traibuenas to determine the irrigation impact. The model calibration (2000–2010) and validation (2011–2020) results for streamflow (NSE = 0.82/0.83) and nitrate load (NSE = 0.71/0.68) were satisfactory, indicating the model’s suitability for use in the watershed. A comparison of the rainfed and post-irrigation periods showed an average annual increase in streamflow (952.33 m3 ha−1, +18.8%), nitrate load (68.17 kg ha−1, +62.3%), and nitrate concentration (0.89 mg L−1 ha−1, +79%) at the watershed outlet. Irrigation also caused seasonal changes by altering the cropping cycle and increasing the streamflow and nitrate export during the summer and autumn when irrigation was at its peak. The increases in the post-irrigation period were attributed to the added irrigation water for streamflow and increased nitrogen fertilizer application due to changes in cropping for nitrate concentration and export. These findings are useful to farmers and managers in deciding the best nitrate pollution control and management measures to implement. Furthermore, these results could guide future development and expansion of irrigated lands to improve agricultural sustainability.Publication Embargo Finite element method for minimizing geometric error in the bending of large sheets(Springer, 2024-10-31) Gil del Val, Alain; Penalva Oscoz, Mariluz; Veiga Suárez, Fernando; El Moussaoui, Bilal; Ingeniería; IngeniaritzaMinimizing geometric error in the bending of large sheets remains a challenging endeavor in the industrial environment. This specific industrial operation is characterized by protracted cycles and limited batch sizes. Coupled with extended cycle times, the process involves a diverse range of dimensions and materials. Given these operational complexities, conducting practical experimentation for data extraction and control of industrial process parameters proves to be unfeasible. To gain insights into the process, finite element models serve as invaluable tools for simulating industrial processes for reducing experimental cost. Consequently, the primary objective of this research endeavor is to develop an intelligent finite element model capable of providing operators with pertinent information regarding the optimal range of key parameters to mitigate geometric error in the bending of large sheets. This prediction model is based on response surface method to predict the bending diameter of the pipe taking into account three main process parameters: the plate thickness, the length, and the roll displacement. These results present promising prospects for the automation of the industrial process because the average geometric error in curvature is recorded at 0.97%, thereby meeting the stringent industrial requirement for achieving such bending with minimal equivalent plastic deformation.Publication Unknown Harnessing the potential of radiative cooling for the built environment: a new comprehensive protocol for materials' characterization(Elsevier, 2024-07-26) Chiatti, Chiara; Marchini, Francesco; Fabiani, Claudia; Kousis, Ioannis; Carlosena Remírez, Laura; Pisello, Anna Laura; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISCThe pursuit of novel materials for radiative cooling (RC) holds immense promise in addressing building energy saving and urban overheating. RC capitalizes on the principle of dissipating heat energy into space, specifically through the atmospheric window between 8-13 μm, to achieve passive cooling of surfaces. However, the absence of a standardized and reliable methodology for characterizing RC materials has introduced inconsistencies in research findings, impeding collective advancements in the field. To address this issue, a dedicated experimental protocol is here introduced, as a unifying benchmark for the characterization of RC materials. This procedure aims to provide comprehensive, consistent, and precise data regarding crucial properties of RC cooling materials, including thermal stability, spectral radiative behavior, and thermal performance under both controlled and realistic boundary conditions. To demonstrate the effectiveness of our proposed methodology, we designed and implemented a comparative study involving an aluminum-based and a Vikuiti-based sample incorporating a silica-derived polymer as an emissive layer. Notably, our findings reveal that the Vikuiti prototype outperforms the aluminum counterpart, primarily attributable to its superior solar reflectance and thermal emittance characteristics. This research not only advances our understanding of RC materials but also offers a crucial step toward uniform characterization methods that can catalyze further research and scaling up of radiative cooling technologies.Publication Open Access Machine learning-based analysis engine to identify critical variables in multi-stage processes: application to the installation of blind fasteners(DYNA, 2020) Murua Etxeberría, Maialen; Veiga Suárez, Fernando; Ortega Lalmolda, Juan Antonio; Penalva Oscoz, Mariluz; Díez Oliván, Alberto; Ingeniería; IngeniaritzaQuality control in manufacturing is a recurrent topic as the ultimate goals are to produce high quality products with less cost. Mostly, the problems related to manufacturing processes are addressed focusing on the process itself putting aside other operations that belong to the part’s history. This research work presents a Machine Learning-based analysis engine for nonexpert users which identifies relationships among variables throughout the manufacturing line. The developed tool was used to analyze the installation of blind fasteners in aeronautical structures, with the aim of identifying critical variables for the quality of the installed fastener, throughout the fastening and drilling stages. The results provide evidence that drilling stage affects to the fastening, especially to the formed head’s diameter. Also, the most critical phase in fastening, which is when the plastic deformation occurs, was identified. The results also revealed that the chosen process parameters, thickness of the plate and the faster type influence on the quality of the installed fastener.Publication Open Access Novel method for an optimised calculation of the cross-sectional distribution of live loads on girder bridge decks(Czech Technical University, 2022) Gaute-Alonso, Álvaro; Garcia Sánchez, David; Calderón Uriszar-Aldaca, Íñigo; Lopez Castillo, Claudio; Ingeniería; IngeniaritzaOne of the main goals in the design of girder bridge deck systems is to determine the cross-sectional distribution of live loads across the different girders that make up the cross-section of the deck. Structural grillage models and current bridge design standards based on a Load Distribution Factor (LDF) provide oversized designs, as demonstrated in this paper. This research introduces a novel method that allows the cross-sectional distribution of live loads on girder bridge decks to be calculated by applying a matrix formulation that reduces the structural problem to 2 degrees of freedom for each girder: the deflection and the rotation of the deck-slab at the centre of the girder's span. Subsequently, a parametric study is presented that analyses the structural response of 64 girder bridge decks to a total of 384 load states. In addition, the authors compare the outputs of the novel method with those obtained using traditional grillage calculation methods. Finally, the method is experimentally validated on two levels: a) a laboratory test that analyses the structural response of a small-scale girder bridge deck to the application of different load states; b) a real full-scale girder bridge load test that analyses the structural response of the bridge over the Barbate River during its static load test. Based on this analysis, the maximum divergence of the proposed method obtained from the experimental structural response is less than 10%. The use of the proposed novel analysis method undoubtedly provides significant savings in material resources and computing time, while contributing to minimizing overall costs.Publication Open Access Quantification of agricultural best management practices impacts on sediment and phosphorous export in a small catchment in southeastern Sweden(Elsevier, 2023) Oduor, Brian Omondi; Campo-Bescós, Miguel; Lana Renault, Noemí; Kyllmar, Katarina; Mårtensson, Kristina; Casalí Sarasíbar, Javier; Ingeniería; Ingeniaritza; Institute on Innovation and Sustainable Development in Food Chain - ISFOODAgricultural activities contribute to water pollution through sediments and nutrient export, negatively affecting water quality and aquatic ecosystems. However, implementing best management practices (BMPs) could help control sediments and nutrient losses from agricultural catchments. This study used the Soil Water Assessment Tool (SWAT) model to assess the effectiveness of four BMPs in reducing sediment and phosphorus export in a small agricultural catchment (33 km2) in southeastern Sweden. The SWAT model was first evaluated for its ability to simulate streamflow, sediment load, and total phosphorous load from 2005 to 2020. Then, the calibrated parameters were used to simulate the agricultural BMP scenarios by modifying relevant parameters. The model performed satisfactorily during calibration and validation for streamflow (NSE = 0.80/0.84), sediment load (NSE = 0.67/0.69), and total phosphorous load (NSE = 0.61/0.62), indicating its suitability for this study. The results demonstrate varying effects of BMP implementation on sediment and phosphorus (soluble and total) export, with no significant change in streamflow. Filter strips were highly effective in reducing sediment (−32%), soluble phosphorus (−67%), and total phosphorous (−66%) exports, followed by sedimentation ponds with −35%, −36%, and −50% reductions, respectively. Grassed waterways and no-tillage were less impactful on pollutant reduction, with grassed waterways showing a slight increase (+4%) in soluble phosphorus and no-tillage having a minimal effect on sediment (−1.3%) and total phosphorus (−0.2%) export. These findings contribute to the ongoing efforts to mitigate sediment and nutrient pollution in Swedish agricultural areas, thereby supporting the conservation and restoration of aquatic ecosystems, and enhancing sustainable agricultural practices.Publication Unknown Size effects in finite element modelling of 3D printed bone scaffolds using hydroxyapatite PEOT/PBT composites(MDPI, 2021) Calderón Uriszar-Aldaca, Íñigo; Pérez, Sergio; Sinha, Ravi; Cámara Torres, María; Villanueva, Sara; Mota, Carlos; Patelli, Alessandro; Matanza, Amaia; Moroni, Lorenzo; Sánchez, Alberto; Ingeniería; IngeniaritzaAdditive manufacturing (AM) of scaffolds enables the fabrication of customized patient-specific implants for tissue regeneration. Scaffold customization does not involve only the mac-roscale shape of the final implant, but also their microscopic pore geometry and material properties, which are dependent on optimizable topology. A good match between the experimental data of AM scaffolds and the models is obtained when there is just a few millimetres at least in one direction. Here, we describe a methodology to perform finite element modelling on AM scaffolds for bone tissue regeneration with clinically relevant dimensions (i.e., volume > 1 cm3). The simulation used an equivalent cubic eight node finite elements mesh, and the materials properties were derived both empirically and numerically, from bulk material direct testing and simulated tests on scaffolds. The experimental validation was performed using poly(ethylene oxide terephthalate)-poly(butylene ter-ephthalate) (PEOT/PBT) copolymers and 45 wt% nano hydroxyapatite fillers composites. By applying this methodology on three separate scaffold architectures with volumes larger than 1 cm3, the simulations overestimated the scaffold performance, resulting in 150–290% stiffer than average values obtained in the validation tests. The results mismatch highlighted the relevance of the lack of printing accuracy that is characteristic of the additive manufacturing process. Accordingly, a sensi-tivity analysis was performed on nine detected uncertainty sources, studying their influence. After the definition of acceptable execution tolerances and reliability levels, a design factor was defined to calibrate the methodology under expectable and conservative scenarios.Publication Open Access Smarterial – Smart matter optomagnetic(2021) Irisarri Erviti, Josu; Marzo Pérez, Asier; Galarreta Rodríguez, Itziar; Estatistika, Informatika eta Matematika; Ingeniaritza; Zientziak; Institute of Smart Cities - ISC; Institute for Advanced Materials and Mathematics - INAMAT2; Estadística, Informática y Matemáticas; Ingeniería; CienciasSmart materials, also known as programmable materials, are a combination of different components that have the capability to change shape, move around and adapt to numerous situations by applying an external controllable field. Previous works have used optically guided matter or magnetically actuated materials, but similarly to soft robots, they are limited in spatial resolution or strength. Here we propose combining a low temperature thermoplastic polymer Polycaprolactone (PCL) with ferromagnetic powder particles (Fe). Focused light can heat this compound at specific locations and make it malleable. These heated spots can be actuated by external magnetic fields. Once the material cools down, this process can be repeated, or reversed. The compound can be actuated contact-less in the form of 3D slabs, 2D sheets, and 1D filaments. We show applications for reversible tactile displays and manipulation of objects. The laboratory team has characterised the density, weight, magnetic attraction, magnetic force, phase change, thermal and electrical conductivity and heat difusión (spread point test) for smart ferromagnetic compounds of different mixture proportions. The main advantages of this smart matter optomagnetic are the high spatial resolution of light and the strong force of magnetic attraction whilst mechanical properties of polymers are practically conserved. Due to the low temperature required and the possibility to use infrared or electromagnetic induction to heat the compound, the smart material can be used in air, water, or inside biological tissue. Eventually, Smart materials will enrich collaborative movements, such as grab and hold, and more complex ones, as reshaping and reassembling.Publication Open Access Three-dimensional finite element modelling of sheet metal forming for the manufacture of pipe components: symmetry considerations(MDPI, 2022) Bhujangrao, Trunal; Veiga Suárez, Fernando; Penalva Oscoz, Mariluz; Costas, Adriana; Favieres Ruiz, Cristina; Ingeniería; IngeniaritzaThe manufacture of parts by metal forming is a widespread technique in sectors such as oil and gas and automotives. It is therefore important to make a research effort to know the correct set of parameters that allow the manufacture of correct parts. This paper presents a process analysis by means of the finite element model. The use case presented in this paper is that of a 3-m diameter pipe component with a thickness of 22 mm. In this type of application, poor selection of process conditions can result in parts that are out of tolerance, both in dimensions and shape. A 3D finite element model is made, and the symmetry of the tube section generated in 2D is analysed. As a novelty, an analysis of the process correction as a function of the symmetrical deformation of the material in this case in the form of a pipe is carried out. The results show a correct fitting of the model and give guidelines for manufacturing.Publication Open Access Topological features dictate the mechanics of the mammalian brains(Elsevier, 2020) Sáez, Pablo; Duñó, C.; Sun, L.Y.; Antonovaite, N.; Malvè, Mauro; Tost, D.; Goriely, A.; Ingeniería; IngeniaritzaUnderstanding brain mechanics is crucial in the study of pathologies involving brain deformations such as tumor, strokes, or in traumatic brain injury. Apart from the intrinsic mechanical properties of the brain tissue, the topology and geometry of the mammalian brains are particularly important for its mechanical response. We use computational methods in combination with geometric models to understand the role of these features. We find that the geometric quantifiers such as the gyrification index play a fundamental role in the overall mechanical response of the brain. We further demonstrate that topological diversity in brain models is more important than differences in mechanical properties: Topological differences modify not only the stresses and strains in the brain but also its spatial distribution. Therefore, computational brain models should always include detailed geometric information to generate accurate mechanical predictions. These results suggest that mammalian brain gyrification acts as a damping system to reduce mechanical damage in large-mass brain mammals. Our results are relevant in several areas of science and engineering related to brain mechanics, including the study of tumor growth, the understanding of brain folding, and the analysis of traumatic brain injuries.Publication Open Access Towards cooling concrete: evaluation of cement and cement composites under realistic climatic conditions(Elsevier, 2025-04-15) Torres García, Alicia E.; Agbaoye, Ridwan O.; Carlosena Remírez, Laura; Goracci, Guido; Lezaun Capdevila, Carlos; Dolado, Jorge S.; Beruete Díaz, Miguel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería; IngeniaritzaFinding scalable, cost-effective and environmentally safe solutions for Passive Daytime Radiative Cooling (PDRC) is essential for addressing energy and climate challenges. This study demonstrates the feasibility of achieving PDRC using only cement-based compounds, without the need for additional whitening agents or other additives. Unlike previous approaches that rely on external additives, the proposed solution leverages two fundamental cement phases—portlandite and tobermorite—offering a scalable and low-impact alternative. The research evaluates the radiative cooling potential of these phases, along with two widely used cements—white cement (WC) and ordinary Portland cement (OPC), by analyzing and comparing their homogenized complex permittivities, derived using the Kramers-Kronig (KK) method. Simulations were conducted to assess the cooling power over one year across three different climates using actual meteorological data. The portlandite exhibits positive Pcool, maintaining a temperature equal to or below the ambient temperature more than 90 % of the time in dry desert and warm temperate locations. Indoor controlled measurements results reveal that portlandite (CH) may exhibit temperatures 15 °C lower than OPC and 5 °C lower than WC.