Forecasting through deep learning and modal decomposition in multi-phase concentric jets

This work presents a set of neural network (NN) models specifically designed for accurate and efficient fluid dynamics forecasting. In this work, we show how neural networks training can be improved by reducing data complexity through a modal decomposition technique called higher order dynamic mode decomposition (HODMD), which identifies the main structures inside flow dynamics and reconstructs the original flow using only these main structures. This reconstruction has the same number of samples and spatial dimension as the original flow, but with a less complex dynamics and preserving its main features. We also show the low computational cost required by the proposed NN models, both in their training and inference phases. The core idea of this work is to test the limits of applicability of deep learning models to data forecasting in complex fluid dynamics problems. Generalization capabilities of the models are demonstrated by using the same neural network architectures to forecast the future dynamics of four different multi-phase flows. Data sets used to train and test these deep learning models come from Direct Numerical Simulations (DNS) of these flows.Comment: 46 pages, 20 figures. Submitted to Expert Systems with Application

Analysis of tribological properties in disks of AA-5754 and AA-5083 aluminium alloys previously processed by equal channel angular pressing and isothermally forged

In the present study, the wear behaviour of two aluminium alloys (AA‐5754 and AA‐5083) is analysed where these have been previously processed by severe plastic deformation (SPD) with equal channel angular pressing (ECAP). In order to achieve the objectives of this study, several disks made of these alloys are manufactured by isothermal forging from different initial states. The microstructures of the initial materials analysed in this study have different accumulated deformation levels. In order to compare the properties of the nanostructured materials with those which have not been ECAP‐processed, several disks with a height of 6 mm and a diameter of 35 mm are manufactured from both aluminium alloys (that is, AA‐5754 and AA‐5083) isothermally forged at temperatures of 150 and 200 °C, respectively. These thus‐manufactured disks are tested under a load of 0.6 kN, which is equivalent to a stress mean value of 18 MPa, and at a rotational speed of 200 rpm. In order to determine the wear values, the disks are weighed at the beginning, at 10,000 revolutions, at 50,000 revolutions and at 100,000 revolutions, and then the volume‐loss values are calculated. This study was carried out using specific equipment, which may be considered to have a block‐on‐ring configuration, developed for testing in‐service wear behaviour of mechanical components. From this, the wear coefficients for the two materials at different initial states are obtained. In addition, a comparison is made between the behaviour of the previously ECAP-processed aluminium alloys and those that are non‐ECAP‐processed. A methodology is proposed to determine wear coefficients for the aluminium alloys under consideration, which may be used to predict the wear behaviour. It is demonstrated that AA‐5754 and AA‐5083 aluminium alloys improve wear behaviour after the ECAP process compared to that obtained in non‐ECAP‐processed materials.This research was funded by the Spanish Ministry of Science and Innovation (former Spanish Ministry of Economy and Competitiveness) through the Research Project DPI2013‐41954‐P

Cartografías participativas y producción de datos sociales en escenarios patrimoniales. Posibilidades de reutilización comunitaria de las “Ruinas de Enacar”, sector Chambeque, Lota, (Chile)

The objective of this research is to provide primary input for possible cultural and tourist reuse of the heritage and mining landscape of the ENACAR Ruins, Chambeque, Lota Alto, Chile. To this end, a collective, cartographic exercise was planned in which inhabitants, local organizations and academic actors interested in exploring the uses and appropriations of the heritage by local citizens participated. The participatory mapping was conducted over several working sessions with the technical support of academics and professionals specialized in industrial heritage. The activities carried out consisted in the historical, current and future analysis of the site. Graphic support was provided through historical photographs of the workers engaged in their industrial work, which facilitated the affective connection with the space, and a presentation with photographs of the site and its buildings in their current state of conservation. Nearly one hundred local actors attended these sessions, which made it possible to collect heterogeneous visions regarding the territory, its value as industrial heritage and possible uses for its cultural and tourist reuse.El siguiente trabajo tiene el objetivo de entregar insumos primarios para una posible reutilización cultural y turística del patrimonio y del paisaje minero de las “Ruinas de ENACAR”, sector Chambeque, Lota Alto. Para ello, se planificó un ejercicio colectivo y cartográfico donde participaron habitantes, organizaciones locales y actores académicos interesados en explorar en los usos y apropiaciones del patrimonio por parte de la ciudadanía local. El mapeo participativo se llevó a cabo durante varias jornadas de trabajo con el apoyo técnico de académicos y profesionales especializados en patrimonio industrial. Las actividades desarrolladas consistieron en el análisis histórico, actual y futuro del sitio, para lo cual se dispusieron soportes gráficos, fotografías históricas de los trabajadores en sus labores industriales -que facilitaron la conexión afectiva con el espacio- y una presentación con fotografías del sitio y sus inmuebles, en su estado de conservación actual. Estas jornadas contaron con la asistencia de casi un centenar de actores locales, lo que permitió recolectar visiones heterogéneas respecto al territorio, sus valores como patrimonio industrial y posibles usos para su reutilización cultural y turística

Analysis of the influence of aging heat treatment on the modification of the mechanical properties of the alloy AA6060 processed by ECAE

En el presente trabajo se ha realizado un estudio de la modificación de las propiedades mecánicas de la aleación de aluminio AA6060 F, al ser deformada mediante deformación plástica severa empleando el proceso de extrusión en canal angular (ECAE). Asimismo, se ha efectuado un estudio del efecto del envejecimiento artificial sobre la modificación de dichas propiedades mecánicas. Para ello, se han realizado tratamientos térmicos a diferentes temperaturas y tiempos de permanencia, efectuando mediciones de dureza, ensayos de tracción, ensayos con péndulo Charpy y técnicas de revelado metalográfico, para conocer los comportamientos mecánicos y el estado del material. Existe un elevado número de publicaciones, que han analizado el efecto de tratamientos térmicos de envejecimiento en aleaciones de la serie 6000. Sin embargo, la aleación AA6060 no ha sido tan ampliamente estudiada. Por ello, en este trabajo se parte de una aleación comercial AA6060 en estado de bruto de colada, lo cual no ha sido estudiado hasta la fecha.In the present work, a study on the modification of the mechanical properties of the aluminium alloy AA6060 F has been made when severe plastic deformation is applied to it through Equal Channel Angular Extrusion (ECAE). Moreover, a study about the effect of the artificial aging on the modification of such mechanical properties has been carried out after having processed the material by ECAE. In order to do this, thermal treatments at different values of temperature and holding time have been performed. Hardness, tensile tests and Charpy impact test, along with metallographic techniques, have been carried out in order to analyse the mechanical behaviour and the state of the material. In spite of the existence of several studies that have analysed the effect of aging thermal treatments on 6000 aluminium alloys, such studies are focused on laboratory alloys with industrial compositions not very usual. Therefore, in the present work, the employed starting material is a commercial alloy as-cast, which has not been studied up to now.Los autores del presente estudio agradecen el apoyo dado por el Ministerio de Ciencia e Innovación (Proyecto de investigaciónMAT2006-14341-C02-02)

Analysis of fatigue and wear behaviour in ultrafine grained connecting rods

Over the last few years there has been an increasing interest in the study and development of processes that make it possible to obtain ultra-fine grained materials. Although there exists a large number of published works related to the improvement of the mechanical properties in these materials, there are only a few studies that analyse their in-service behaviour (fatigue and wear). In order to bridge the gap, in this present work, the fatigue and wear results obtained for connecting rods manufactured by using two different aluminium alloys (AA5754 and AA5083) previously deformed by severe plastic deformation (SPD), using Equal Channel Angular Pressing (ECAP), in order to obtain the ultrafine grain size in the processed materials are shown. For both aluminium alloys, two initial states were studied: annealed and ECAPed. The connecting rods were manufactured from the previously processed materials by using isothermal forging. Fatigue and wear experiments were carried out in order to characterize the in-service behaviour of the components. A comparative study of the results was made for both initial states of the materials. Furthermore, Finite Element Modelling (FEM) simulations were used in order to compare experimental results with those obtained from simulations. In addition, dimensional wear coefficients were found for each of the aluminium alloys and initial deformation states. This research work aims to progress the knowledge of the behaviour of components manufactured from ultrafine grain materials.The authors of this present research work acknowledge the support given by the Spanish Ministry of Economy, Industry and Competitiveness (former Spanish Ministry of Economy and Competitiveness) through the Research Project DPI2013-41954-P

Analysis on the manufacturing of an AA5083 straight blade previously ECAE processed

Over these past few years, there have been a large number of technical papers published related to the problem of improving the mechanical properties of materials obtained through severe plastic deformation. Nevertheless, the number of technical papers dealing with improvement in the mechanical properties of mechanical components manufactured from submicrometric grain size material has not been so proficient. Therefore, in this present research work, a straight blade has been manufactured starting from AA-5083 previously processed by ECAE twice (N2) with route C.This material will be manipulated so as to be isothermally forged at different temperature values.This present research work shows the results that are inherent in an improvement in themechanical properties and the microstructure achieved in the thus obtained components, compared with the starting material. In addition, the optimum forging temperature to achieve these components will be determined. As shown in this research work, it is possible to obtain submicrometric grain size mechanical components with a higher mechanical strength than those obtained in nonultrafine grained materials. The originality of this research work lies in the manufacturing of actual mechanical components from ECAE processed material and the analysis of their properties.The authors acknowledge the support given by the Spanish former Ministry of Science and Innovation (now Ministry of Economy and Competitiveness) under the Research Project DPI2010-18941

Comparative study of the damage attained with different specimens by FEM

Trabajo presentado a The Manufacturing Engineering Society International Conference, MESIC 2015 (Barcelona)This present research work deals with the analysis of the design of different specimen geometries so that by finite volume simulations, the appearance of cracks may be predicted in the case of forging processes. To this end, each of the geometries selected are studied by means of compression tests between plane shape dies in the same conditions (T = 25 ºC). On the one hand, a value for the critical damage value is obtained by applying the Cockroft-Latham’s criterion and on the other hand, a damage distribution along all the specimen volume with the aim of defining a specimen which shows the most likely place for the crack to appear. This crack location may be also determined through visual inspection with the aim of being able to evaluate this experimentally in the near future.The authors acknowledge the support given by the Spanish former Ministry of Economy and Competitiveness under the research project DPI2013-41954-P