Research on the Friction Properties of DP600 Stainless Steel as a Function of Bending Angle and Pin Diameter

[EN] The rapid evolution of materials and manufacturing processes, driven by global competition and new safety and environmental regulations has had an impact on automotive structures (Body In White; BIW) manufacturing. The need for lighter vehicles, with more equipment, that are safer and eco-friendly at the same time, relates to the entire life cycle of the car. Car and steelmakers agree that weight reduction is possible, and the solution involves the use of new advanced high-strength steels. Thinner and stronger materials lead to higher demands on stamping, the most used manufacturing in BIW parts. The use of advanced high-strength steels raises new challenges, especially concerning the lubrication between the die and the sheet. To study the lubrication conditions of the stamping process, a sheet metal forming a simulator was developed. The simulator consists of two cylinders that pull the strip of steel and a pin in between. The angle between the cylinders can be adjusted from 0 to 90 degrees, which allows analysis of the effect of the stamping angle. The pull force and velocity can be set and measured, and the peripheric pin velocity, the strain, and the strain velocity can be measured as well. In this work, the tribological properties of Dual-Phase 600 stainless steel using different processing conditions have been analyzed. To this end, a factorial experiments design with twelve parameters that compare the behavior of different angles and diameters was run. The results showed that the friction coefficient increases by increasing the bending angle and decreases with pin diameter.Sanchez-Caballero, S.; Sellés, M.; Pla-Ferrando, R.; Segui Llinares, VJ.; Peydro, MA. (2021). Research on the Friction Properties of DP600 Stainless Steel as a Function of Bending Angle and Pin Diameter. Materials Proceedings. 3(1):1-7. https://doi.org/10.3390/IEC2M-09248173

Non-invasive monitoring of pH and oxygen using miniaturized electrochemical sensors in an animal model of acute hypoxia

Background: One of the most prevalent causes of fetal hypoxia leading to stillbirth is placental insufficiency. Hemodynamic changes evaluated with Doppler ultrasound have been used as a surrogate marker of fetal hypoxia. However, Doppler evaluation cannot be performed continuously. As a first step, the present work aimed to evaluate the performance of miniaturized electrochemical sensors in the continuous monitoring of oxygen and pH changes in a model of acute hypoxia-acidosis. Methods: pH and oxygen electrochemical sensors were evaluated in a ventilatory hypoxia rabbit model. The ventilator hypoxia protocol included 3 differential phases: basal (100% FiO2), the hypoxia-acidosis period (10% FiO2) and recovery (100% FiO2). Sensors were tested in blood tissue (ex vivo sensing) and in muscular tissue (in vivo sensing). pH electrochemical and oxygen sensors were evaluated on the day of insertion (short-term evaluation) and pH electrochemical sensors were also tested after 5 days of insertion (long-term evaluation). pH and oxygen sensing were registered throughout the ventilatory hypoxia protocol (basal, hypoxia-acidosis, and recovery) and were compared with blood gas metabolites results from carotid artery catheterization (obtained with the EPOC blood analyzer). Finally, histological assessment was performed on the sensor insertion site. One-way ANOVA was used for the analysis of the evolution of acid-based metabolites and electrochemical sensor signaling results; a t-test was used for pre- and post-calibration analyses; and chi-square analyses for categorical variables. Results: At the short-term evaluation, both the pH and oxygen electrochemical sensors distinguished the basal and hypoxia-acidosis periods in both the in vivo and ex vivo sensing. However, only the ex vivo sensing detected the recovery period. In the long-term evaluation, the pH electrochemical sensor signal seemed to lose sensibility. Finally, histological assessment revealed no signs of alteration on the day of evaluation (short-term), whereas in the long-term evaluation a sub-acute inflammatory reaction adjacent to the implantation site was detected. Conclusions: Miniaturized electrochemical sensors represent a new generation of tools for the continuous monitoring of hypoxia-acidosis, which is especially indicated in high-risk pregnancies. Further studies including more tissue-compatible material would be required in order to improve long-term electrochemical sensing

Study of the mechanical properties of recycled abs and recovery throught mixing with SEBS

Recovery of recycled acrylonitrile butadiene styrene (ABS) through mixing with styrene-ethylene/butylene- styrene (SEBS) has been studied in this paper. To simulate recycled ABS, virgin ABS was processed through 5 cycles, at extreme processing temperatures, 220 oC and 260 oC. The virgin ABS, the virgin SEBS, the recycled ABS and the mixtures were mechanically characterized after the various cycles of reprocessing in order to evaluate their corresponding properties and correlate them with the number of cycles undergone. The results show that tensile strength of ABS remains practically constant as the number of reprocessing cycles increases, while in the material injected with SEBS the tensile strength decreases. Concerning the Charpy notched impact strength; the values of the ABS reprocessed at 220 oC remain more or less unchanged, while the values for 260 oC show a significant decrease. The adhesion of the SEBS causes, in both cases, an increase in impact strength.Peydro, MA.; Juárez Varón, D.; Sanchez-Caballero, S.; Pla-Ferrando, R. (2014). Study of the mechanical properties of recycled abs and recovery throught mixing with SEBS. Annals of The University of Oradea. Fascicle of Management and Technological Engineering. (1):83-86. http://hdl.handle.net/10251/57748S8386

Design and optimization of intake manifold in a Volkswagen car

The objective of this work was to develop a new design of a high performance intake manifold through a combination of CAD and FEM. First a FEA model was done, which included a complete thermal and structural analysis of the new intake manifold and the contact area between the aluminum coupling, using the combined tools of CATIA, ANSYS WORKBENCH, MATHCAD. Then several composite prototypes were made where analyzed.Martínez Sanz, AV.; Sanchez-Caballero, S.; Viu Betrán, A.; Pla-Ferrando, R. (2011). Design and optimization of intake manifold in a Volkswagen car. Annals of The University of Oradea. 2:29-34. http://hdl.handle.net/10251/35901S2934

Gear train optimization using evolutionary algorithms

[EN] This paper shows a genetic algorithm (GA)-based optimization procedure for gear trains design. Gear design uses simultaneous discrete (P.E. pitch) and continuous variables nonlinearly related. However, unlike GAs, most optimization methods are only suited for continuous design variables. This paper uses GAs as a tool to achieve not only the optimal design, but also a series of near-optimal designs. To achieve this objective, first the optimization problem is formulated. It must be multiobjective (maximum strength, minimum energetic losses, etc) and restricted. A mechanism to transform the constrained problem into unconstrained thought penalty functions is proposed. Recommendations on the objective function and penalty terms are also suggested. Next a design variables coding and decoding method, as well the genetic operators of reproduction, crossover and mutation are presented. Finally, it is analyzed an example in which the developed genetic algorithm has been used, comparing the obtained results from a previous optimization.[ES] En el presente artículo se expone un procedimiento de diseño de transmisiones de engranajes basado en los Algoritmos Genéticos (GA). En el diseño de engranajes se emplean simultáneamente variables continuas y discretas (p.e. el paso) relacionadas entre sí de forma no lineal. Sin embargo, a diferencia de los GAs, la mayoría de métodos de optimización sólo funcionan adecuadamente con variables de diseño continuas. El presente trabajo emplea los GAs como una herramienta que nos permita encontrar no sólo un diseño óptimo, sino también un conjunto de diseños cercanos al mismo. Para lograr este objetivo, en primer lugar se formula el problema de optimización. Este debe ser multiobjetivo (máxima resistencia, mínimas pérdidas energéticas, etc.) y restringido, proponiéndose un mecanismo para transformar el problema restringido en no restringido mediante el empleo de funciones de penalización. También se proponen recomendaciones sobre la elección de la función objetivo y los términos de penalización de la misma. Seguidamente se plantea el método de codificación y decodificación de las variables de diseño, así como los operadores génicos de reproducción, cruce y mutación. Finalmente se analiza un ejemplo en el que se implementa el algoritmo genético expuesto, comparando los resultados con los obtenidos en una optimización previa.Sanchez-Caballero, S.; Sellés Cantó, MÁ.; Peydro, MA.; Pla-Ferrando, R. (2013). Optimización de transmisiones de engranajes mediante algoritmos evolutivos. 3c Tecnologia. (7):1-17. http://hdl.handle.net/10251/36305S117

Design of a test bench for experimental measurement of structural joints rigidity

This work was born as a result of the need of measuring the mechanical behaviour of a set of structural elements and joints, to correlate the experimental results from previous on road with the bidimensional Finite Element Models ones. To such purpose the Adapted Vehicles and Transport research group has developed a new test bench that will enable more accurate results from Finite Element Models which will allow optimizing the frame structure of heavy vehicles as semitrailers.Sanchez-Caballero, S.; Pla-Ferrando, R.; Juárez Varón, D.; Peydró Rasero, MÁ. (2014). Design of a test bench for experimental measurement of structural joints rigidity. Annals of The University of Oradea. Fascicle of Management and Technological Engineering. (3):106-109. http://hdl.handle.net/10251/57747S106109

Nuevas técnicas de optimización de estructuras

La optimización de estructuras ha sido objeto de un intenso estudio durante los últimos cincuenta años. Aunque la Programación Matemática fue inicialmente la técnica más empleada, ha sido reemplazada por un conjunto de técnicas meta heurísticas. Entre ellas los Algoritmos Genéticos es la técnica más importante. Este trabajo realiza una pequeña descripción de cada una de estas así como sus principales trabajos e inconvenientes. Finalmente, se analiza la estructura más empleada como banco de pruebas para posteriormente mostrar y comentar los mejores resultados obtenidos hasta la fecha.Sanchez-Caballero, S.; Sellés Cantó, MÁ.; Pla-Ferrando, R.; Peydro, MA. (2012). Nuevas técnicas de optimización de estructuras. 3C Tecnología. 1(3):1-19. http://hdl.handle.net/10251/30123S1191

Analysis of a polymer-coated steel for food can manufacturing

A new polymer coated steel has been developed and is being considered for food-container applications. This material presents an interesting extension to previous research on polymer laminated steel in ironing. A design-of-experiments matrix has been prepared using the commercial software package Stat-Ease, and involved varying the die angle, speed, reduction in thickness and tooling temperature. Formability data has been obtained both through experimentation and theoretical modelling with upper bound methods.Sellés Cantó, MÁ.; Pérez Bernabeu, E.; Pla-Ferrando, R.; Sanchez-Caballero, S. (2014). Analysis of a polymer-coated steel for food can manufacturing. Annals of The University of Oradea. Fascicle of Management and Technological Engineering. 3(3):110-113. http://hdl.handle.net/10251/57738S1101133

Data adquisition system development for on road measurements in heavy vehicle frames

Many different methodologies have been used for heavy vehicle frames design, whose goal is to optimize the predicted frame behavior. On road measurements will allow to increase the precision when predicting the stress and strain on the frame. Keeping the abovementioned information in mind, and given the importance of this process, our research group concluded it is necessary to develop a Data Acquisition System capable to carry out this task both quickly and accurately. This paper will show the developing of the Data Acquisition System used in several on road test of a semitrailer frame at Applus IDIADA test track. Th is report will explain all of the possibilities that the testing offers from data capture to its processing and analysis.Sanchez-Caballero, S.; Pla-Ferrando, R.; Pérez Bernabeu, E.; Sellés Cantó, MÁ. (2014). Data adquisition system development for on road measurements in heavy vehicle frames. Annals of The University of Oradea. Fascicle of Management and Technological Engineering. (1):277-280. http://hdl.handle.net/10251/57740S277280

Prior knowledge elicitation: The past, present, and future

Specification of the prior distribution for a Bayesian model is a central part of the Bayesian workflow for data analysis, but it is often difficult even for statistical experts. Prior elicitation transforms domain knowledge of various kinds into well-defined prior distributions, and offers a solution to the prior specification problem, in principle. In practice, however, we are still fairly far from having usable prior elicitation tools that could significantly influence the way we build probabilistic models in academia and industry. We lack elicitation methods that integrate well into the Bayesian workflow and perform elicitation efficiently in terms of costs of time and effort. We even lack a comprehensive theoretical framework for understanding different facets of the prior elicitation problem.Why are we not widely using prior elicitation? We analyze the state of the art by identifying a range of key aspects of prior knowledge elicitation, from properties of the modelling task and the nature of the priors to the form of interaction with the expert. The existing prior elicitation literature is reviewed and categorized in these terms. This allows recognizing under-studied directions in prior elicitation research, finally leading to a proposal of several new avenues to improve prior elicitation methodology.Fil: Mikkola, Petrus. Aalto University; FinlandiaFil: Martín, Osvaldo Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina. Aalto University; FinlandiaFil: Chandramoul, Suyog. Aalto University; FinlandiaFil: Hartmann, Marcelo. University of Helsinki; FinlandiaFil: Abril Pla, Oriol. University of Helsinki; FinlandiaFil: Thomas, Owen. University of Oslo; NoruegaFil: Pesonen, Henri. University of Oslo; NoruegaFil: Corander, Jukka. University of Oslo; NoruegaFil: Vehtari, Aki. Aalto University; FinlandiaFil: Kaski, Samuel. Aalto University; FinlandiaFil: Bürkner, Paul Christian. University Of Stuttgart; AlemaniaFil: Klami, Arto. University of Helsinki; Finlandi